PDEs: How Much Extra Can They Handle?

Question for the PD experts:
Increasing the injection quantity in a common rail (PD) system naturally also increases the injection duration. However, I believe that, due to the higher injection pressure, the limit of the possible and safe increase in injection quantity is not as restrictive in a common rail system as it is in a conventional pump-injector (VP) system, at least in terms of injection duration.
But what about PDEs? Can we generally assume that a certain percentage increase (x%) is easily achievable, or where should the limit be set?
When I compare Ulf's ASZ (presumably a specific product or technology) to my AXR (likely another product or technology), I see an increase in performance of approximately 23%. With my AXR, the increase is even higher, at 30%.
I've found a little bit of information here /viewtopic.php?t=3185 already. However, it wasn't continued to the end. According to that thread, 30% are likely completely harmless. Are there any further insights on that now?