When I changed my fluid & filter the plug was stuck also. Banged on the plug head some, whacked the allen a few times, banged some more and finally it came loose. Guess I should have lubed it up before reinstalling it - DUH!
Maybe the Mag-Hytech folks should not install the plug, instead put it in a bag with the allen wrench and seal with special instructions to lube and install @ XX inch pounds. If they did this, then we could only blame ourselves. MHO