When I paid the bills at the end of April, I didn't see a gas bill. This is pretty normal, because it often gets delivered a day or two after I pay the bill, or I misplace it. I gave them some money anyway.
For the end-of-May billing, I found something from the gas company. According to Dominion, we used 1.8 MCF of gas. Over two months, from March 24 to May 24.
For comparison: the bill says that our average monthly use is 13.0 MCF. During the winter months, we were up to 30 MCF pretty often. The bill shows a usage of about 10 MCF for last May (although it doesn't show the estimate for the previous april for comparison.) This is a stunning drop.
It's a bit odd that the bill doesn't include a drop for March, when the siding was finished in February. My rationalization is that we were using more gas while the siding was being put on, which wasn't reflected in February's estimate, and was then balanced out by less gas used during March.
The bill includes a line of 'balance from last bill', and a credit for the same amount labeled 'cancel billing'. I presume this is shorthand for 'whoa nellie, our estimates sure were off. We're just going to cancel that estimate and bill you for two months as if we hadn't made that estimate'.
(The previous estimate was $221.80; the revised bill for two months is $48.45. Since I sent them $500 last month since I couldn't find the bill, I may not have to pay a bill for quite some time.)