The problem with A & C doing the avionic work is experience NOT ability. As you all say, on newer aircraft there is not a lot goes wrong with them avionically, well not on a regular basis. Therefore, it may be months between A & C with extension getting a few meaty avionic jobs. With there being less avionics per shift at most places, they tend to get all the jobs and learn the quick fixes. Quick being the operative word in a ramp environment. Fix it, get it out, no delay.
We all know the FIM can be usefull or it can send you down the garden path.
Its the beancounters choice. How big a delay do they want ?????????????????????