" I just discovered that the reason my Throttle Position Sensor was giving lower voltage outputs or % open readings was because mechanically the sensor’s armature was only being rotated through about 1/3 of its range of motion when full throttle was engaged"
Was this exploration triggered by a CEL indicating a problem or did you check the TPS voltage for some other reason? If it was a CEL, were the stored codes P0122 or P0123 which suggests a problem with the TPS measuring circuit. Or was it a P1243 or P1244 which is a position sensing error which can be caused by (among other things) a discrepancy between the APS and TPS. P1243 and P1244 are part of the DBW error checking which has a set of codes from P1241 to P1248. Any of the P1241 - P1248 codes would suggest that you might have a DBW issue.
I don't have access to my service manual so I can't provide any absolutely correct advice. When the gear box is in neutral, there may be inputs into the ECM which prevent the DBW from going 100% open (can't remember whether that was an NSX thing or some other car). The best way to check the TPS operation on the throttle body may be with everything shut off, disconnect the TPS plug and measure the TPS wiper resistance value. Manually operate the throttle by sticking your finger in the TB and pushing the throttle plate open and then check the resistance range as you go from closed to full open on the throttle plate. If you don't get the full range of resistance change then you may have a mechanical linkage problem with the throttle plate to TPS; but, I am not sure how that could happen. I think you can do this test with the throttle body.
If you are getting error codes for the DBW system, the best thing to do would be to get the service manual and go through the diagnosis applicable to the error code.
