So SPANIM ,"I",, resets SPHOME data while executed. How do I work around this issue?

Are you using a constant home position? If so, you can make it part of the sprite definitions themselves by using SPDEF. One variant of SPDEF allows you to create a definition based on an existing definition, but changing only certain attributes (in this case, the origin position).

I did not use SPDEF. I haven't used it before but I suppose it's a good time to learn how it works. Thanks for your help!