Hit % on bosses ??

I have a question about the hit % on the bosses. If a boss with hit 60% and splash dam strikes how is it calculated? is it 60% to hit at all or ?? Cause I just fought Wild Mary which has 50% hit and for 12 rounds she didn't miss once which is hard for me to see with a 50% hit. Please explain cause in my head this isn't possible with a 100% hit for 12 rounds.

a miss is not really a miss, but only minimum damage, so all units (except for skunk) will always do damage, but the amount varies,

i think the acc is chance of max damage

If you toss a coin, the chances are that it will fall heads up 50% of the time. In reality, that's never the case.
Chance is not a guarentee.