Actually, there were 3 rooms--the main dining area often pictured (7 courses), Queen Victoria's Room with fireplace and Chef's Table, both 10 courses.
I agree that it's difficult to impossible to predict what one's price might be. Though not wine drinkers, we've rarely been able to resist one or two upgrades. (Ahhhh, the white truffle!)
Also, the upgrades in QVR or CT tend to be better quality, more distinctive than those offered with the 7 courses in the main room. For instance, from one of the four designated Japanese regions for Wagyu beef rather than Wagyu-style raised in the US or elsewhere. The menu description tells you what you'd be getting.
Previously, we generally spent $700-$750ish for us two, with 1-2 upgrades, after-dinner coffee, tax and tip included. No telling how much higher the base price will be once V&A's reopens.
I agree with McCrae that June is wishful thinking given how skimpy menus were at the upscale restaurants when we were there in November.