Practice makes perfect ... so clearly more practice is needed.
I figured the 2nd sock would go smoothly, now that the 1st sock is done with lessons learned. But after I TINKed back the 1st row of the Heel pattern for the 4th time before finally getting the pattern established correctly, I realized I'd been overconfident.
When I bought the yarn for these socks, I bought the required skein plus an insurance skein. Because it's one thing to have extra, but quite another thing to be short. Probably only the most experienced, skillful knitters confidently purchase materials according to the pattern without padding the quantity.
It looks like I'll have enough yarn to make another pair of socks. And I think that's what I'll do. Because, clearly, in my case, more practice is needed.