To clarify, you rate to score 2 trump tricks and partner's bringing something to the party but not much. Hopefully it's useful. Sure, you beat it 2 when kj9x are in dummy, but they make an over when declarer holds that. I'm guessing that on average it's about 50-50 = and -1. But you're risking 170 to win 100, plus you're giving info to declarer who might otherwise take a line that depends on a split or something and go down in a making contract. Now you ring up +100 and +790. Ime, the +3 from +200 v +100 isn't worth it the times you're wrong.
Edit: yeah you probably avg 2.5 trump tricks and partner somewhere between 0.5 and 1 trick.