I had precisely this kind of freewheel... I couldn't get it to budge, and broke the tool. The LBS couldn't get it to budge, and told me they didn't want to damage their tool. The damage to the slots means that somebody else has already tried to remove the freewheel, and gave up.

I didn't think of the destructive removal method, plus I was looking for an excuse to install an old IGH that I had just cleaned up, so it was time for a new wheel.

Win - win.