25 PSI is close to 70' of head loss which is pretty high. Even so, a 2 HP full rated MaxEPro will have about 100 GPM at 70' of head which would be 25 GPM per jet. This would seem to be more than enough flow for each nozzle since most jets require only 15 GPM. What kind of jets do you have? Are there any other outlets in the spa, bench, floor, etc?

If your jets require high flow, one alternative would be to replace them with ones that do not require as much flow to operate.

Also, I would agree with the pump manufacture given the pipe size you have it probably does not make sense to increase the pump HP but as I said before, you should have sufficient flow.