FSBUS Up/Down object

[Erups]

I noticed a particular behaviour of this object:
if you simply "click" it, instead of obtaining the "sum" of the value to the one already present in the offset, you get the application of that value.
I know i can't really explain it so an example sounds better.
Say i want to use the Up/Down to move the flaps on the cessna.
I then set the step to 5461.
This way (THEORETICALLY) i should get
0; 5461; 10922, 16383
which are 0°, 10°, 20° and down.
Instead i get 5461 when using UP;
and -5461 (that gets translated to 16383) when i use the DOWN.
This does not happen if i hold the buttons down, and the accelerate function takes on.
In fact the accelerate function does what it is intended to do: sum up the values.
It's when you are only clicking it once, that this does not happen.
I hope this is clear enough.
Regards