Daan - it takes 5 days to post on Doom9 when you join. The idea is to get you to lurk and search first. You will be allowed to post in due course. I don’t visit here a lot and I doubt mpucoder does at all, so it’s worth waiting to post at the author’s help site.
As for saving MXPs and it changing parameters, I have experienced this on and off - but with audio delays - never celltimes. I think it is fixed now.
Are you using the freeware or payware version? Your log shows the scenes starting at the times you wanted. If you like, post the IFOs and we’ll take a look at them.