FWIW as a sidenote I just wanted to point out that it seems the system tracked pixel 'virginity' based simply on whether they'd been touched at all before, including corrections; rather, it was background pixels that didn't charge the extra cooldown, from what I could tell.

Sorry for the silly nitpicking about wording, though given that the Canvas treated these two properties separately I wonder if this might be useful information for whoever runs this next time.