Frank,
I have personally found that the penis takes some time “getting used to” the working out thing. Just be careful and go slow, he will tell you when he can take more and really start to gain. If you are doing your workouts, and don’t feel like you’ve worked out, then you’re not working it out intensely enough (I say intense, because I don’t mean repetitions, I mean pressures/forces). Sounds like you’re not over-doing it because you have no negative PI’s.
I have noticed this also, you gain in stretched flaccid before you gain in erect. I think of it this way: The workout is PROVIDING the space for it to grow into by stretching things out. The erection then needs to grow to FILL that space. This is why I do edging sessions with a cock ring on to force-inflate everything for a time and get the erection to grow into the meat. Have you tried a rubber cock ring to see if your clamped erection better matches your stretched size?
Mike