I have 5400 running with VPX. Flaps through the VPX. Upgraded from 4500. My flap position shows retracted on the EFIS when the flaps are retracted. Shows full flaps when fully extended. But at 50% flaps, it indicates 75% flaps on the EFIS. On the 4500, it showed 50%. I checked and re ran the calibration. The AD value at fully extended is 226 (of 255). At retracted is 0. At 50% setting for the flaps the AD value reported by both the EFIS and VPX is 114. The 5400 considers this 75%. How do I change the 5400 to consider AD of 114 to be 50% flaps?