But it isn't about your transfer flight 
What are your arguments? And what is to be calibrated about a transponder?
On the first point, I have no idea what you mean by that.
Regarding the second point, the arguments should be obvious to you. Laws and rules must be followed even if you don't like or agree with them.
The third point you make is way off the mark. There is, as with any radio equipment a necessity to ensure that what is transmitted is of the required standard: so not to cause interference with others and be readable by ATC, to ensure it is reliable and that the mode C transmission is accurate within the usable limits. Some of this is adjustable by a radio engineer.but as often as not the unit will require sending to a licenced radio workshop for repair.
Mode C is still accepted and approved for most of the lower levels of controlled airspace.
The document linked by MOONRAT makes it very clear that it relies on contributions to remain accurate. Anything to do with EASA is fluid and requires continuous research for uptodates. I gave up many years ago relaying accurately to my students information I knew yesterday still being true today let alone being true tomorrow.