What is the rule where if you lose while in your renchan extra round, all of those points go to the winner?

I'm very new to Riichi Mahjong. I was playing against ai, and got exhaustive draw in tenpai a few times in a row. I got a few extra East 2 rounds. In ren 7 an ai won, and I went from 45k to 18k, and the AI took all of that from me (it was ron, btw). This was the first time I lost in an extra round, so I didn't know about this (all extra rounds were forced). I was playing Riichi Mahjong from Flyout Studios, defautl settings.