Just use a little common sense in your versioning to make it easier for everybody. If you know you're going to terminate part 1 at 0.6c, then change it to part 1 - v1.0.i am retarded and making an excuse to abandon it. Jesus christ!
Then, when you start on part 2, it's part 2 - v0.1 , 0.2, etc. with minor revisions appending an a,b,c on the end of it?
Is it really that difficult/illogical? You're not coding for a multinational Fortune 500 company - you're making an AVN in Ren'Py. There are hundreds (thousands?) of games on this site, most in various state of update/disrepair/abandonment - none of which conform to a regular update schedule. It's next to impossible to keep all of that straight - crazy nonsensical versioning like that (Part 1 v0.6c being the end, then starting with Part 1 v0.7) is just needless.