I recently bought a new spectrum Tx and went about putting all my present aircraft info into it from old Tx. Much to my surprise and misfortune I found that this does not work that well. Although most of the previous info was reasonably close to being correct, not entirely. I had 20 aircraft in the old Tx that I copied into new. Went about checking each one in air and found further trim settings required. Overall usually nothing serious but definitly requires caution when doing this. be forewarned if you do so.

That's all TXs and not just any one brand, there is usually a little difference. I'm still using my old Futaba 9-C and when I build and set up a plane for other people using the same TX as mine, once in a while there is some trim needed. Not always and not a lot but it happens.