I think.. the best thing is decarboxylation first in the oven. the water boiling and the butter simmering at 150-200 I think is just fine. the boiling water moves the thc and butter cells and the simmering bonds it to the fat cells.. i guess

when I did this I didn't really hear the butter simmer much, just a tad.

anyway my stove doesn't reach 250 degrees even on high. it stays a little above 100 degrees Celsius.