I use a switch on my flap handle, so the unit is in climb mode when the flap is in position 5 or higher.

I checked the p-tot using a simple blow test but nothing more sophisticated..

Alas I cannot find a way to view the IAS on the LX. An option I guess it to turn on the LX's IAS (logging) sentence and compare it to observations.

Another problem I'm having with the LX that could possibly be related is that when on the ground, the LX always thinks it's in flight, which makes it impossible to change certain settings or to transfer a flight log. That would happen, I think, if it is getting an indicated airspeed.