Yeah I dont think it would be too much of a problem. I think the issues arise when you make mistakes like, for example, place the wrong grade with a particular class or something. Honestly, you never know though so it would probably be best to call AMCAS and ask. They may even be able to tell you if the class you are not certain if it is bcpm actually is one or not.
I took some liberties and placed some engineering courses under BCPM. They moved a few of the classes, but my primary was verified within 24 hours (I also submitted on the first available day).