I think that capping the lower bosses at 30 (Dark Lord) is a good idea because it gives a chance for lower level people to still participate at the events with a high chance of getting the girl.

...And a Finalmancia with a level higher than yours probably pays a crud load of money upon defeat, so you are probably still ahead of the game with a 58% winning rate, than a capped lower level with 100% success rate and lower money.

In other words... I like it the way it is...