Calibration of SRRC upgraded FMTs (Fineness and Maturity Testers) using the constant offset technique has proved successful as demonstrated previously (Von Hoven et. al, 2001). However, one of the FMTs shipped to SRRC for upgrading and calibrating was loosened during shipment. Due to a series of problems, the FMT was not air-tight and thus not generating reliable data. Once the system was leak free, it was upgraded and calibrated as the unit that preceded it. A comparison of micronaire, fineness and maturity between the two upgraded and calibrated FMTs demonstrated that the two FMTs were generating statistically similar data.