What numbers are you getting for steps per 100mm? I hadn't calibrated my extruder and it had the factory setting of 831 steps per 100mm. I ran a calibration test and found that instead of 100mm it only pulled through 87mm.

According to the gurus, Calibrated E steps(100) = (100/measured feed) x original E step(100) value

For me this is Calibrated E step (100) = (100/87) x 831 = 1.15 x 831 = 955.

OME