Well Murray isn't 6'3" either according to him stating that he's 187.5cm tall (6'2"), so y'know. It may be height with shoes and/or early in their careers, in their early 20s. Then it could be rounded up or down, 5'9" could be 174 to 176cm, 5'10" could be 177 to 179, and between 174 and 177cm you already have more than an inch (2.54cm). If he or/and the ATP rounds up on 176cm it easily becomes 5'10".
In short? I doubt it matters that much considering it may be the same for every other pros.