64 bit application install question

I'm running 7 Ultimate 64 bit on a 64 system....my question is...certain application set up's are offer a set up that's made for both 32 and 64 bit systems...the same set up for both rather then separate ones....but when I install these app's...many of them install themselves in the 32 bit Program folder rather than the 64 bit one....why is that ? One would think that it should go to the 64 bit...