The great part about photoreading is that it is built in layers. One of the benefits is that you go over the text superreading and dipping more than once. That's how you build up the comprehension.
Have you ever notice how they build up a house going round the whole house evenly. Adding a bit of all the walls. Not just finishing one room at a time? Well it's the same deal with learning. You build a structure and return to it at each stage to build on that structure. It's easier to add on the parts while you're still building.
Yes go over it superreading and dipping however often you need. You don't need to spend much time with it, 2 to 10 seconds per page and repeat.
Alex