It depends on the school. Some schools can receive elctronic submssions of the entire app, and thus get them faster, and others are dependant on AMCAS sending them paper copies (which I think they do on some sort of batch schedule, which I'm not up on this year) and so only get the preliminary basic info transmitted electronically. So it's not all AMCAS's fault when schools take forever.
One could surmise (but this is pure speculation) that the schools that don't have on-line secondaries would be the ones most likely not to be able to receive on-line transmissions of entire apps.
MCAT scores take awhile, both to get to the schools, and then for the schools to get them into files. Last year it was 2 weeks at the minimum after applicants were receiving their mailed scores.