Need help with positioning problem

When i enter an mdi command to move an axis at feedrate of 30 ipm my machine moves smoothly to the commanded position however if i issue the same command but use a feedrate of 50ipm my machine still moves smoothly but does not make it to the commanded position. The dro says it does but it falls short of the physical movement.What values in fhe .ini file should i be looking at in order to correct this.I ran the latency program and feel comfortable with that value. Im using gecko g320x drives. Im also running mach3 and the machine works fine with that software so i also feel confident in the mechanics of the machine.

Thanks