The people I know who breed won't generally chance it with a breed as tiny as a Pap. Two inches is quite a lot in a tiny dog - 1/4 of the height of the female - and she is on the small side of the standard. If you approach the size difference in terms of percentage of the female's size, the difference becomes quite apparent.
It's a risk that I, as a bitch owner, would not take. I would look for a male that more compliments her, if I were to breed her.