>>715505201
I wouldn't be surprised, but...It'd probably be easier to just make sure that PREPARATIONS ARE COMPLETE by copying the same save file to all three slots.

>>713782979
>Gaster's response to you copying one file to all three slots is "PREPARATIONS ARE COMPLETE."
>each save file has subtle differences in it, like what's in Asriel's drawer or item descriptions
There's absolutely going to be some crazy shit involving jumping between three timelines.