I wanted a similar effect with respect to time. I didn't need "At the tone the time will be FOUR, THIRTY-TWO..." but more like "It's around four-thirty." In my case (with Pfeil's help) I built a Condition Statement that divided a 24-hour clock into quarter hours offset by seven minutes from the norm, so "Around noon" started at seven minutes before twelve till seven minutes after, when it changed then to "Bout a quarter past twelve" and so forth. It was a bit of work but the results are great. Now if I ask at 3am it can say "For pete sake, its 3 in the morning, go to bed" and so forth.
Doing so for numbers in general might be something you can achieve with tokens (something I am just beginning to glimpse). But I'd think that up front you could declare tokens that state your preferred rounding parameters, so >750 but <1200 might be "Around a thousand". You'd need a table of them I'd think, but when the API pulled in a value, it would run against the declared tokens and the right text would spill out in the SAY command.
Sadly, I am probably butchering the explanation, but while it might not be a checkbox feature just yet, I think with a bit of work you can get the effect you are looking for.