The other thing to keep in mind is that it doesn't take a set amount of time, as much as it happens on a set periodic schedule.

So a transfer that happens one day later, if it misses a weekly "slot", may take an extra week, compared to a transfer that happens one day earlier.

I find it curious, by the way, that someone would transfer Choice points out on Jan 1. Most people transfer just before the end of the year that the Choice points are due to expire. I would think the least likely time that someone would therefore transfer points would be immediately after the start of the new year. (That's why you're not likely to find other people with reports of transfers done on Jan 1, just more reports of transfers done in the last week of December. Btw, I did one of those too, but my experience was the same as above.)