Yes, some of the RealSimGear hardware/firmware combinations have this action reversed. Its easy to change by editing the CommandMapping.ini file found in the SR22/22T folders.
Look for the GFC700 sections [RealSimGear-GFC700#4] and [RealSimGear-GFC700#6].
Find the commands:
ENC_Wheel_UP@sim/cockpit2/autopilot/altitude_mode#4=sim/autopilot/vertical_speed_up
ENC_Wheel_UP@sim/cockpit2/autopilot/altitude_mode#5=sim/autopilot/airspeed_down
ENC_Wheel_UP@sim/cockpit2/autopilot/altitude_mode#6=sim/autopilot/altitude_up
ENC_Wheel_DN@sim/cockpit2/autopilot/altitude_mode#4=sim/autopilot/vertical_speed_down
ENC_Wheel_DN@sim/cockpit2/autopilot/altitude_mode#5=sim/autopilot/airspeed_up
ENC_Wheel_DN@sim/cockpit2/autopilot/altitude_mode#6=sim/autopilot/altitude_down
And change the last values to match what you need to do, ie:
ENC_Wheel_UP@sim/cockpit2/autopilot/altitude_mode#4=sim/autopilot/vertical_speed_down
ENC_Wheel_UP@sim/cockpit2/autopilot/altitude_mode#5=sim/autopilot/airspeed_down
ENC_Wheel_UP@sim/cockpit2/autopilot/altitude_mode#6=sim/autopilot/altitude_up
ENC_Wheel_DN@sim/cockpit2/autopilot/altitude_mode#4=sim/autopilot/vertical_speed_up
ENC_Wheel_DN@sim/cockpit2/autopilot/altitude_mode#5=sim/autopilot/airspeed_up
ENC_Wheel_DN@sim/cockpit2/autopilot/altitude_mode#6=sim/autopilot/altitude_down
Save the file, and reload X-Plane