I think with stock injectors you should not do but a tweak of offset as you did and not as big a change as +/- 20 % as you could force the injectors to command on before or after the sparkplug fired

The delay, 2 parts, 1 is was the existing values not correct for the engine makeup and 2 did offset values for engine makeup require values different then what you had ( assumed stock values) not valid for your engine's needs.


Keep in mind if voltage level changes it then has effect on which offset row and its values are used.

Thus if for some reason voltage is low then so it the voltage to injectors thus different offset value row is being used and those values for delay might not suit the engine's needs.