Yes this is a one of a kind analysis and I have no data to compare with.
I too have killed much more (subjectively) very high altitude bombers in the last year than ever before, but I don't think it's caused the Me 410. First, this trend with me started before the Me 410 arrived and second there are a lot more deadly buff killing planes out there. Spending often more than half of my time in bombers myself, I still see many more other deadly interceptors.
The thing is: The very high altitude (25k+) bombers I see are mostly heading for the strats. Only since August 2012 we have such an working, attractive central target. Yes, the central strats were the before for like 2-3 years, but after an initial 2-3 tours everybody noticed how pointless they were and stopped attacking them. And when we had zone factories, nobody had to fly several sectors through enemy airspace to attack one, which is one of the main reasons for high altitude bombing.
Tactically (attacking bases) I still see them much lower, though I would (subjectively) agree that the number of 20K bombers (and fighters!) has increased here as well. I think one of the reasons could be the removal of the 15k 'haze blanket' ... older players will remember this. This thin layer of haze made many bombers flying just below of it. And in case of fighters, it was a clear line tagging anyone above an "alt monkey"