Agree with blanch13 to a point. I should've mentioned the major outliers, with RP on the low side (I had a 65 overall RP become a Type B recently) and SSs on the high.
As for SP, I don't see very many 70-72 SPs who aren't Type Bs due to their sizable population within the game. Whereas a flukish population of outstanding shortstops might lead a 75 overall SS dropping to Type B status, pitchers tend to be a little steadier with respect to population dynamics. It's by no means ironclad, but in my experience you won't go wrong betting on a 70-73 to be a Type B, while 74+ is good for Type A.