In the above example if he was taking all those lipos to the same voltage cutoff, the diff numbers would imply there was a prob - poss just normal aging. Capacity falls as lipos get old.

Your 2000mah 2S taking 1500mah on re-charge is just about perfect. Lipo does not like or tolerate deep discharges - defined as more than 80% of capacity so discharging more than 1600mah would not be in the interest of long lipo life. This is how you should set your lvc - so when it activates and you recharge, you don't put more than 80% of capacity back in on charge.

You could discharge it deeper, but you could also have it puff unexpectedly after several cycles from the stress of doing that too. You should never discharge a lipo below ~3v/cell (6v for a 2S).