Batman is an Olympic-class athlete. That includes weight lifting. Not incidentally, it is the STR he would have on a conversion from the Mayfair DC Heroes game. The same conversion, iirc, gives the Joker a 30 STR. The joys of insanity.
Captain America is more than just human. I've never agreed that "maximum human potential" is the same as "maximum currently possible", which is about where NCM defaults in my mind. Rogers has scaled a wall carrying his motorcycle in one hand. You want to refer to the current MCU, you've got him lifting a motorcycle with three dancing girls sitting on it. The trailer for AoU shows him dismounting from his bike and throwing it without suffering from the force of momentum of movement when he lands on his feet. Also not incidentally, 35 is within the range of numbers when you convert his MSHRPG (FASERIP) stats to Hero.
Basically, those numbers feel right to me for those characters.