I think most SPs are afraid to advertise their real measurements & age, because any guy with experience seeing SPs will likely add several inches & several years in his head, assuming they are lying. For example, a 25 yr old might be advertised as 22, but if she was actually advertised as 25, prospective clients would assume she was actually 30.
I agree that repeat business depends on a lot more than one's age, weight & measurements, but it does affect first-time clientelle, as when a client is just reading or hearing the SP's description that is all he has to go by (other than her "menu" of course).
I don't think the measurements/ weight misunderstanding has to do with women not loving their bodies (although many unfortunately don't) or entirely with the fact that most clients will add a few inches & a few pounds, because it has been my experience that many men do not understand women's measurements or what is "average", plus they expect us to weigh substantially less than a man of the same height would. I have had men who swore that I couldn't weigh over 100 lbs, because for some reason they think a petite woman must weigh 100 lbs or that that is the ideal weight. I do not think they were saying this to try to flatter me, BTW.
But I bet a lot of women couldn't guess a man's weight or measurements acurately either.