The Custom Calibration has been in all AirMagnet Survey Pro versions, but I have not used it until recently.
By using an offset of -7 across all 5GHz channels, the Proxim adapter can now closely emulate what a Cisco 8821 Wireless IP handset looks like in an active survey.
Without creating a custom adjustment, there can be at times a 5 to 10dBm RSSI difference between what the AirMagnet adapter indicates during the survey and what the Cisco 8821 indicates in the same location as shown below.