Knockoff Bosch Injectors - anyone have experience with them?

Anyone have any experience tuning with the knockoff Bosch injectors? This is my first time trying to tune a car with them and I am noticing that the car gets increasingly rich the longer you drive it. Is this typical behavior, if there is a typical behavior for these cheap injectors? The customer isn't convinced that the injectors are the issue but I can't see what else it could be as the car is running stock air temp./coolant temp. fuel compensation tables, so something must be changing with the physical setup.

The longer story if you care to read it:

I am tuning an Evo X for someone using ECUFlash/Evoscan. I had told him to replace his existing injectors with ID1050X injectors as the car was running increasingly leaner under boost the longer you drove it. He told me he bought "the injectors" and had them installed and was ready for me. The first warning sign was that the scaling/latencies I ended up with for these injectors were far different from ID1050x values I have used for Evo 8s, but being that it is a different platform and ECU, I didn't think too much of it. However, in tuning the car (road tune), I discovered that the longer I drove it, the richer it got, to the point that the idle short-term fuel trims maxed out negative with the car still idling at 12.5 - 13 AFR and under boost everything is in the 10 -10.5 AFR. The opposite of what it was doing before. I parked the car overnight and drove it out again the next day and the idle AFR and trims were good and AFR under boost in the 11.2 to 11.4 range with the car at operating temperature. But after an hour of driving, I was back to what I observed the previous day. I decided to check the injectors and saw that they were not ID. He then advised that he didn't buy ID but bought $100 EBay 1000cc injectors because he wasn't convinced the injectors were the source of the original problem so he didn't want to shell out IDs.

How many hours can you afford to spend to save a few hundred dollars?

Are the calculated injector pulse widths changing when the engine goes richer? Or are they staying the same?

David Furgeson, I don't plan to spend any more time on it without new injectors, apart from reviewing the logs I already have. I have wasted too much time on this car already, what with other fuel delivery issues it has been having previously.

Black Rex, I compared idle logs but it is a bit difficult to tell anything for certain for a few reasons. The parameter in the data file I am using to log IPW in Evoscan lacks granularity. i.e., different actual values of IPW can show in the log as the same value. Also the changes in AFR bring about changes in idle rpm and load so it is hard to tell if you are comparing apples to apples. I am embarrassed to say that I didn't compare logs under boost/high load, where it should be easier to discern differences. I will do that tonight plus spend more time looking at the idle logs.

"Other delivery issues" - first thing I was going to ask is if you've been monitoring the fuel delivery pressure, as that sounds more like a creeping regulator or, possibly, a bad regulator seal that's progressively failing and allowing more or less fuel through, depending on whether it's a dead-head or recirculating system.