Yes, we really can put any prescription in any dive mask. All our work is custom so we can accommodate even the highest prescription. The PD is the distance from the center of one pupil to the center of the other. This is different for each person. It is essential for accurate dispensing to place the optical center of the lens over the center of the pupil.
Any offset can induce prism, actually changing the apparent power of the lens.
We ask you to dot your pupil center before shipping your mask to us. Do this by wearing the mask, looking into the distance at a point, and marking that point on the face plate with a felt tipped pen. Another method is to have another person mark the center of your pupils while you look into the distance. Thats usually what happens. If so, send us the broken bits, suitably wrapped.