I imagine that Thrust Lever consisting of two throttles with two axis, one for the left engine and one for the right engine. The axis in this configuration should go from 0 to 100 (for example)
But in the case of the A320 throttle this goes beyond 0 (negative) and in that phase it must trigger the reverse.
Normally an axis that does the Thrust does only that, while that of the Reverse does only that too.
Therefore for that device to work correctly they must work on the software together with ASOBO.
And perhaps this is the real reason that blocked the distribution of that device.