So I'm going over a whole bunch of SNGs on holdem resources calc just to check mistakes and all that. I see a spot in a triple up SNG..(top 3 out of 9 get the same amount) where we're down to 4 players aka the bubble, and UTG w/ 41 bb folds.. button min raises w/ 21bb stack, sb folds w/ 54bb's and I'm in the BB w/ ATo. I wasn't exactly sure what to do so I went to the advanced hand section of the holdem calc and allowed for flat calls and 3bet shoves.. I put in villains range for how wide he was opening.. and holdem calc told me to defend 87.7% of hands and 3bet the other 12.3%.... How can this be correct? Is there something about triple-up SNGs that I'm not understanding?

Thanks to anybody that can clear this up!!