So, last time, I had a doubling time of something crazy like 34 hours during the first week. I blamed it on switching labs between the two tests. Cornell claimed to be worried about multiples, which is sort of crazy; you change the initial conditions, but not the mechanism of increase, and Betabase shows (as you'd expect) that the doubling times aren't all that different.
I had blood run again this morning, 14dp3dt. God only knows when they'll get the progesterone number back (a week from Thursday?), but they managed to run the HCG in-house (like they're supposed to! today's phlebotomist didn't even believe me when I told her how they'd sent the last one out!), and it's up to 437. Which gives me a crazy-crazy-crazy doubling time of 28 hours and change.
I suppose that, technically, I did switch labs again... only 10 miles apart, not hundreds. Still.