Food for thought.
I switched my air fittings to larger 3/8" ones for my spray equipment
and just to keep everything the same, I also switched them on my
Sears impact wrench too.
I couldn't believe the difference it made, I have much more torque now.
The female disconnect of a std 1/4" fitting has a hole inside about
half the size of the fitting inlet, that's the bottleneck.
A bigger hose didn't make a difference but the new fittings sure did.
So if you're not getting the torque you think you should,
try the bigger fittings.
Home Depot has a 3/8" kit for about $10.00,
it connects to the std 1/4" air hose ends.