Hardware Throttle Override GF-TQ6

I have a GF-TQ6 hardware throttle module and my settings for the NGX are set to have the hardware throttle override in Hold and Arm mode only. However, when the autothrottle is in N1 or FMC speed modes I try to keep the hardware throttle levers matched to the autothrottle setting by using the blue indicator and I find the engines reacting when I change the hardware thrust lever position. For example, I will be in a descent ("Arm" Mode) and I manually pull the thrust levers back to reduce the thrust. Then when I level out during the descent, the autothrottle will enter "FMC Speed" mode and increase thrust as designed to maintain speed in level flight. This leaves the engine display with the indicated engine power at ~60-80% N1 and the blue arc (showing the hardware thrust level position) at about idle thrust. All of this so far is what I expect based on the documentation. However, if I then start to advance my hardware levers to match what is being commanded by the autothrottle, I will see a decrease in N1 as the engines try and match my hardware setting. Once I stop moving the levers (at about where the setting was), the engines settle back into autothrottle control. Based on what I have read, my expectation is that in this last case, the sim should NOT react to my adjustment of the thrust levers to try and match the existing autothrottle commanded position. Am I incorrect, or is this a bug?Thanks,Bill Rowe