Songbook transpose not only one octave

Could make Songbook transpose not only one octave?
Adjusting Up and down transpose can be upper or lower all more octaves.
If wrong changing, press reset can be solved.
This function is very important for my work for different singers to sing the same song in a short time to change the transpose in the same score file without using computer to adjust score files in lite small Android or iOS device.
Please add this function to song book!!! I really need this function to make work easier.
Thank you very much.