Could the Aermacchi MB339 DME be looked at please, it is fixed on 114.5 MHz and only works at Palmdale California and gives some unhelpful ranges to a VORDME in northern Italy and to one in remote Nevada. The distances to go in a route work OK.
It seems the DME uses the frequency selected on the rear seat and doesn't shift when you use the CONTROL SHIFT function. I've fixed that now internally.
As a work-around: You can either just briefly switch to the rear seat and set the same VOR frequency or you just fly it from the rear seat entirely and make sure you set on the CONTROL SHIFT buttons: