Yeah, i noticed that, too. Though I'm sure sounds in ff7 CAN overlap. I may be wrong, though. However, i would assume the "new sound" would cut off the "old sound", and not visa versa.
What someone would need to do is get the sound info from the psx version and compare it side-by side with the pc version. I'm sure the sound is IN the game somewhere, however, it may have gotten corrupted, or possibly misnamed.
Or maybe use ff7snd by fice and just listed to all the sounds till you find it,, but that would involve knowing exactly what you're looking for, and as i never played ff7 on the playstation, i don't think I'd be of much help here... *shrugs*
Also, i dunno how many people had decoded the DAT file format for us to properly edit it so we could get the sound working again...