[arthrodriver]

To prove the 19 ft lbs try it with a new copper washer. Then undo it and see if the washer has deformed itself (expected). The next try with the same washer will take a little more. I don't think 19 foot lbs is excessive and may even be a little light. This situation is somewhat like a spark plug torque. These typically take 15-20 ft lbs in an aluminum head, and also rely upon a crush washer. IMO

Jay, Please know I am an old seasoned home hobbyist and some things I do may not be to the letter. For instance, yes, I confess to reusing the same sump plug gasket on my cars for years. I use the drip test. If no drip it's ok. When first starting out it is probably good to heed the warnings in factory manuals about "discard and use only new parts" until you get some wrench time. As noted, however, you will work harden the copper washer each time you reuse it and chase slightly the torque you sense you need (or measure). Without too much cynicism some of guidelines are really ridiculous IMO. Case in point. A tapered steel diff or trans plug (like a pipe thread) will go on indefinitely. Just keep everything clean and do use a torque wrench on these. The friendly Mercedes dealer wants $7 a pop for such a rugged, reusuable plug.