Just my opinion from time doing op. history and primary document readings (these are from the soldiers to each other). With the soviets, literally the numbers I just have to ignore and focus on the orders. All the general staff studies I have contain soviet estimates of german losses and forces that are inane.
With the Germans, I have rules of thumb- like divide their tank 'kill' claim by two-three and ignore how many tank were recovered or total loss (war is random). Their intel. tends to be closer to the mark-although not close enough- this is just a hunch from observation and confirmation.
US is somewhere between the Germans and Soviets, but closer to the Germans.
You are totally correct with the different measurements thing. Ultimately with war I like getting the numbers but consider having a basic knowledge of what they went to battle with, and their reinforcements ultimately more useful. Also, logistics. The rest- the losses, and whatever are sadly only guesswork.
Overall, I think people sometimes get too wrapped up in numbers
True people get to wrapped up in numbers. Altough they are an indication it is hard to avoid nitpicking.
I almost never read the numbers of enemy losses estimated by the other side, regardless of country. Too many divisions have been "annihilated" without being told so or the annihilation having noticeable effect on their advance.
Or they simply suffered well over 100% casualties.
It is alot more fun to simply try to find corresponding reports from both sides of the same engagement and try to figure out the performance.
Sometimes you find engagements described as huge clashes from one side and as skirmish form the other.
Own losses are often much better recorded because the need for reinforcement and other factors. Those are often accurate no matter the country. (Of course barring wartime public publications.)
And guys you should really try to see differently on the old Soviet archives. Even Mr Glantz ranks their recordkeeping in par or over the German ones. I remember seeing some lecture with him on youtube where he did comment on it. But as always what is recorded and what is show in as important as what isn't.