You do realize that the factory injector values are going to be off for anything other than 58 psi, correct? I'd highly suggest you get your fuel pressure back to the factory 58 psi.
What AF meter are you using?...the injector duty cycle was still at 110%. i replaced my injectors with some out of a low milage 02 ws6(28.8lbs) and my injector duty cycle is still around 105%.
I've seen the stock 28.x injectors make it to 390 to 420 without issue, but this also depends on the age of the injector and accuracy of the wideband (making sure it isn't tuned too rich). I actually saw them make it to 43x range once on an '02 Z06, but this is a RARE example.