I recently noted some oddities concerning the distance between MUC and LHR.

For my flights between those airports I received slightly different amounts of avios quite as if the distance between those cities fluctuated.

(Just reporting the Tier Bonus Avios (=100% of miles distance) not to let different booking classes cause some confusion.)

Nov 2016: 578 Avios
Jan 2016: 580 Avios (LHR drifting away from the continent due to plate tectonics?)
Jul 2017: 590 Avios (Wow, didn't know continents moved so fast. So maybe some early repercussions of Brexit?)
Aug 2017: 578 Avios (LHR nearer to MUC again? Indication of a soft brexit? Reversion of continental drift? Or just more penny pinching by Cruz?)

Flights in July were AA coded, but that shouldn't make any difference, I thought.

Did anybody notice similar phenomena concerning other city pairs?