I'm doing more and more keyboards recording sessions for various artists, bands, etc. and I've had a recurring issue that I now want to discuss with pros

It's been maybe 3 or 4 times when a client would come back to me, days, weeks or even months after a session was done, asking if I could change "the tones a little bit" or the key of the whole thing or some little details like that and they all assume it would be easy to fix because they assume I record my keyboards in MIDI and I can just run the MIDI through the keyboards again and change little details. But I don't (always) record the MIDI ! And actually when I do, it's mostly just because I want to get a "quantized" option or something that should sound programmed and not played.
So my question is, should I always record the MIDI when I do sessions ? So I can provide this option of changing sounds, tempos, keys, etc.. ?? I feel like yes, I should...but I don't...sometimes I record really quickly and go with the flow, and somehow recording the MIDI is messing with my work flow.
Any pro keyboard players here that does session work ? Do you provide that option or just provide the audio and that's it ?
Bonus question : How many revisions of a recording should I provide for the first agreed price ??
Thanks !!