Injectors are calibrated during manufacture and every injector has a unique calibration code. When an injector is replaced (or position swopped) then the unique code has to be updated/entered into the engine ECU.
No injector delivers the same amount of fuel for a given rail pressure and activation/open time. The injector code tells the ECU what amount of fuel it delivers at a calibrated pressure and open period. This allows for the ECU to adjust its parameters to ensure correct fueling.
So there are two possible causes for your problem
1) you have the wrong injectors
2) you have incorrect calibration data
