hehe cool ok the pics did indeed look as if the lighting was a bit more sophisticated than an onboard flash... so that should give you a good bit more play.. I've no experience using strobes hands-on but have a pretty solid grasp of the theory.. I'd say this might just be a good old fashioned case of trial and error playing between shutter/ aperture/ flash strength, as it seems A-dep and M are kicking out different numbers from the metering..

I agree onboard flash kinda sucks, always diffuse/bounce it if I can, or just bumb the iso up and screw the flash. I'm confident you'll find a way to get the results you're after, you have a real good style with your postwork, and a good eye for portraits.. can't see a little thing like lighting flummoxing (that must be the first time I've ever typed that word!) you..

all the best
Adam

Adam Edwards Photography