Follow-up on lawn mower with bad spark-plug threads

Follow-up on the engine with bad spark-plug threads that you were good enough to advice me on a couple months ago    .
The hole was definitely too small for the bigger sparkplugs, so I decided to go with the helicoil.
The motorcycle shop was willing to do it for 6 dollars for the helicoil and iirc 30 dollars installation.
Also, on E-bay, I found a lower cost brand, Recoil Fix-a-thred (no a), and the vendor said it was better because the insertion tool was metal instead of plastic. And he said that the coils themselves were the same as the other brand used. Helicoil brand? I think his buy-it-now price was about 40 dollars and I was willing to spend the extra to have the tool. (not sure about the price. I don't see them for sale now, and ebay purged my Watch list of the old items (probably because they purge completed auctions after 30 or 60 days or something.)
(although now I see a Helicoil brand kit for 12MM with less than 4 hours to go (15:16PST on Saturday) whose current bid is 20.50 dollars plus 8 dollars shipping. This week there seems to be a lot of helicoil stuff, but not that one guy. Last time a lot of that one guy, but little else. :) )
But I also took the head off the engine to clean inside and I noticed -- well I didn't notice enough and I'm very confused now -- that even though the spark plug fell out if placed in halfway and turned it, if I pushed it in all the way, there seemed to be good threads in the head at the very bottom (of the head, not the plug).
I feel like a fool, and that I wasted your time. I apologize. Although I am glad to learn what I did about helicoils, and maybe telling you about the off-brand and ebay is enough to make up for wasting your time.
Maybe sometime next summer I'll have to take the plug out for some reason, and I'll figure out why it was so hard for me to screw in. I've never had a problem before putting in a sparkplug and maybe I'm not such a fool, somehow.
Meirman -- If emailing, please let me know whether or not you are posting the same letter. Change domain to, if necessary.
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