It must be registering as full throttle if you get WEP.
WEP won't run unless you're at the stops already.
Open up Aces High, offline or online. go to clipboard, controls, map controllers, and on your throttle select the axis you have mapped to throttle and hit the "advanced" button.
This will pop out a side page on the clipboard. Move the throttle to maximum and minumums. Does one of the vertical display boxes have a green lines that moves as you move the throttle? See if it goes all the way up or down.
Also, try calibrating just this axis. Don't forget to try returning the lever to the 50% poing before clicking the button to accept your new calibration.
In general, if you calibrate in windows, then calibrate in AH, you should be good to go.
Meaning Windows may only see 95%, but in AH it will set new max/mins based on what it can calibrate in-game. It will use what you have as its max/mins.