I'm sure you do consider it fair. Wasn't questioning your integrity at all. However, 80/20 I believe you'll find are 1966 and earlier; check your xrf gun (you might want to return it as defective) but if its on the mark, you should really check out the numismatic vatue of those coins---probably rare & worth even more than what you're asking. Also, I believe $1 face value canadian contains 23.32 grams (at least that's what the site displays.) So, that part of the equation seems to be about right; key is that word "if." Kitco buys 800 silver @ .305 / gram, and 1966 & older canadian @ .299-----That works out to about 7 times face value with it being of course in american dollars....do the currency exchange and you're pretty much there. Just send it to them would be my suggestion and actually, if you put it on Ebay you'll probably do even better.
Cheers,
John