I just came back from a trip with my parents, and unfortunately I believe we've mixed up our laptop chargers (I have a SR MBP, and my mom has a MB) in the same travel bag. I've heard how it's okay for MBs to use MBP chargers, but not as optimal for MBPs to use MB ones because of power issues. Anyways, I tried looking at both charger units, and aesthetically I couldn't tell the difference between them, down to the small print #s. Is there anyway I can tell the difference? I've also noticed that on many occasions, the "green/amber" charging status light on the MagSafe area has turned off even whilst plugged in... is this something to note or just a small detail to ignore? I just want to make sure I'm using the right stuff for my MBP... thanks!