So you dont even know if the shock is working? do you know what a shock is suppossed to do? do you not know what each knob does? Yea just keep sending it out. its bound to be close.
If it sags to far, you dont need a longer shock. you need a stiffer spring. You say it sags to far with a 500lb spring? somethings not right. I have gotten away with a stock spring on arms up to +8 majority of the time at 200lbs.
theres 2 springs I use, stock and spacer it up for adjustment. and a stiffer spring for +8 arm or longer. These shock places are worthless sometimes. they are just throwin springs at it from an uneducated guess. I have real world testing on several bikes and weight riders.
When you felt lower pressure coming out, it felt low cause it wasnt firing. It will never shoot out hard when not firing even with tons of compression. So this way is almost impossible to tell compression. you need a compression tester and not harbor freight.