I'm not certain I followed what you mean, but the PSR-I455 has three features that affect the pitch of the notes, as described on page 34 of the Owner's Manual:
Tuning - This setting lets you shift the overall pitch of the instrument within a range of approximately -50 cents to +50 cents. The displayed setting is for Concert A-- the A above Middle C-- which normally has a pitch of 440.0 Hz, but changing the pitch of Concert A affects all other notes by the same number of cents. The TUNING can be set from 427.0 Hz to 453.0 Hz in steps of 0.2 Hz. This type of tuning is usually called "fine tuning" in MIDI, to distinguish it from the next type of tuning. The Tuning function does not affect the sound of the Drum Kits.
Transpose - This setting lets you shift the overall pitch of the instrument within a range of -12 semitones to +12 semitones. For example, if you want to transpose from C to G, you could set Transpose to -5 so Middle C actually plays the G below Middle C (down a fourth), or set Transpose to +7 so Middle C actually plays the G above Middle C (up a fifth). This type of tuning is usually called "coarse tuning" in MIDI.
Pitch Bend - The Pitch Bend Wheel lets you gradually shift the overall pitch of the instrument up or down, depending on which direction you move the wheel. The Pitch Bend Range lets you set the range of the Pitch Bend from +/-1 semitone to +/-12 semitones. The wheel recenters itself when you release it. Note that Pitch Bend actually affects only one or two of the instrument parts or MIDI channels-- the Main Voice and Dual Voice, which are normally associated with channels 1 and 2-- so it doesn't actually affect the pitch of the entire instrument the way Tuning and Transpose do.
There are also three additional settings that affect the pitch of the three basic keyboard parts. They are the Main Octave, Dual Octave, and Split Octave. They let you shift the Main Voice, Dual Voice, or Split Voice in whole octaves, within a range of -2 octaves to +2 octaves.
Note that the Tuning, Transpose, and Octave settings are cumulative. For instance, you could actually shift the Main Voice within a range of -3 octaves to +3 octaves by setting Transpose to either -12 semitones (down an octave) or +12 semitones (up an octave) and then shifting the Octave of the Main Voice from there.
Page 32 lists the settings which are saved in the Backup memory, such that they'll be remembered even when you turn off the keyboard.
Some settings are automatically saved in the Backup memory, while others are not. On page 32 these are listed where it says "Function Settings (page 48)." Note that the Tuning setting is automatically saved in the Backup memory, but the Transpose, Pitch Bend Range, Main Octave, Dual Octave, and Split Octave settings are not. This means whatever you set the Tuning to will be automatically remembered and restored even if you turn the keyboard off and on, whereas the Transpose, Pitch Bend Range, Main Octave, Dual Octave, and Split Octave parameters will automatically revert to their default settings when you turn the keyboard off and on.
Some settings can be saved in a Registration memory, while others cannot. On page 32 these are listed where it says "Parameters that can be memorized to Registration Memory." Note that the Transpose, Pitch Bend Range, Main Octave, Dual Octave, and Split Octave settings can be saved in a Registration memory, but the Tuning setting cannot. This means that even though these parameters-- save for Tuning-- will revert to their default settings if you turn the keyboard off and on, you can restore them to your various preferred settings by recalling the appropriate Registration memory. Note that since Tuning cannot be saved in a Registration memory, you cannot save various preferred Tuning settings to different Registration memories for easy recall.
If I followed your post correctly, I take it that the Tuning parameter is the one that's giving you trouble due to it's being automatically saved and restored.
The simplest solution to your issue is to get into the habit of going into the Function menu after turning on the keyboard and going to the Tuning function. You can quickly restore any parameter to its factory default setting by pressing the [+] and [-] buttons at the same time while you are viewing that parameter in the Function menu. So basically, your startup sequence would be as follows:
(1) Turn on the keyboard.
(2) Press the [FUNCTION] button.
(3) Press the [CATEGORY +] button 4 times to advance to the Tuning function.
(4) Press the [+] and [-] buttons-- the ones on the numeric keypad, also labeled [YES] and [NO]-- at the same time to reset the Tuning to its factory default setting of 440.0 Hz.
Another possibility would be to use MIDI to set the keyboard's Tuning to 440.0 Hz or some other desired fine tuning. The MIDI message for setting the fine tuning is described in the MIDI Reference booklet, available at Yamaha's website.
If you have the PSR-I455 connected to a compatible computer or smart mobile device, you could send the appropriate MIDI message to the keyboard from that device.
An alternative might be to create one or more MIDI "song" files, one for each fine tuning that you'd like to be able to quickly select. The file wouldn't actually contain a "song" per se, just the MIDI message that sets the keyboard to a particular fine tuning. Then you could recall any of those fine tunings by pressing the [SONG] button and selecting whichever "song" file contains the fine tuning you want to recall. It isn't even necessary to press the [START/STOP] button to start playing the song, because the act of merely selecting a song in the panel display will automatically load the song's initial settings into the keyboard.
But frankly, the simplest solution is to just get in the habit of always resetting the Tuning parameter whenever you turn on the keyboard, as described above.
EDIT: On rereading your post, I'm thinking that you might be asking about how to maintain the Transpose setting when switching voices, as opposed to how to reset the Tuning.
As mentioned above, Transpose can be saved to a Registration memory, but it isn't automatically saved in the Backup memory. Not only will it revert to its factory default setting of 0 (no transposing) when you turn the keyboard off and on, but I believe it also reverts to its factory default setting when you select a new Main Voice, because each preset voice will change a number of other settings-- Reverb Type, Chorus Type, Harmony On/Off, Harmony Type, Arpeggio On/Off, Arpeggio Number, Dual On/Off, Dual Voice, and the various parameters for the Dual Voice, in addition to the various parameters for the Main Voice.
The only solution I know of, aside from manually changing the Transpose setting each time you select a new Main Voice, would be to set up the keyboard ahead of time with the various settings you want to use at various points during your performance-- including the specific Main Voice, Dual Voice, Split Voice, and all of their associated parameters-- and then save each of those setups to different Registrations so you can recall them as desired while you're performing.
Note that although there are only 32 Registration memories, you can save a User File to a USB thumb drive, and each User File will contain all 32 Registration memories plus any User Songs and User Styles. You can have up to 100 different User Files on a given USB thumb drive, so that lets you put together a number of setups that you want to use again later, and save them to different User Files, or even to different USB thumb drives.
