On 17 Jan 2015, trader_4 wrote in
alt.home.repair:

Adaptive recovery takes care of that, it also works for AC, when
that is set back. As I said, mine hits the target time, closely,
always getting there by the time it's supposed to.

Hopefully I'll know in a few days. I returned and replaced my
questionable thermostat and installed the new one last night. I think
it may have come on at a more reasonable time this morning, but I
didn't manage to rouse myself to know for sure.