Regarding PIC time towards ATP mins--I am 99% certain SIC time for an airline counts as 1/2 towards ATP PIC mins.
So, if you started at Air Midwest with 300TT (assume about 250 of that is PIC, not dual), you would calculate it this way:
1500 PIC req'd - 250 PIC = 1250 PIC needed
1250 PIC = 2500 SIC required to meet ATP PIC minimums = 2 yrs left-seat, conservatively.
I might be totally wrong, but I think this is how it works. That's one other side of MAPD/low time reqs, is that Mesa actually prefers low-timers due to the longer period of time they get to keep you @ $19/hr.
Correct me if I'm wrong.