[harveyjdavis]

To KNS using allen wrench:

Then I'll bet you are torquing by feel, and not much more than flattening the crush washer. You can't confidently get 18 to 22 FT-lbs without a torque wrench, unless you practice doing precisely that and are thinking about that, without a torque wrench you have to go by your body force and the moment arm of the wrench or allen tool.