Chicken house
This whole issue revolves around the issue of what bringing into service actually means.
To most of the world bringing a radio system into service means fitting a new system, so that means a new rack, radio and all the things you require to make a radio system work.
Just taking a radio box out of an aircraft and refitting another box of the same part number IS NOT bringing a new radio system into service, it is carrying out maintenance on the radio system fitted to the aircraft and I see nothing to stop this practice under EU regulation until 2018 when the change over period has ended.