At Universal I'm pretty sure the answer is wrong. Best to call the hotel directly and ask. But I'm almost certain 5 is 5, not 5 + a baby.
But trust me on this one ... unless you love being on top of one another, a standard room at RPR will not hold 6 comfortably. Two queen beds, a rollaway bed, plus whatever the baby sleeps in? If someone gets up in the middle of the night to go to the bathroom, it's going to be an obstacle course. You really, really need to be the type of family that doesn't spend any time in the room at all to be able to pull that one off.