Nobody except me maybe? That's why when I asked, no one could answer as it is a rarely-encountered scenario.
Yes, only the first 3 IPPT are paid. But the amount to me is really insignificant, that's why this wasn't a factor at all. (It may be to other people though)
Due to real life commitments, I was really free last year, but knew I would be really busy this year. That's why I wanted to do more sessions last year to reduce my obligation for this year.
Furthermore, I find IPPT much more "chill" than RT. You don't have to follow the pace of the instructors. In extreme case, you can even do what Supporter said: 1 sit up 1 push up walk 30 min 2.4km. Whereas RT is more "siong". (I guess this is subjective though? Some people chill their way through RT also)
All in all, I'm happy things worked out, and just like to share this info with other people who may encounter same scenario as me.