In both cases, the Pentagon says it has "low confidence" in the figures, due to gaps in information, operational security and deliberate attempts, probably by both sides, to mislead.
Tellingly, this is the one place where attempts have been made to alter the documents to make it look as if Ukraine is experiencing the worst casualties.
A version which appeared on a pro-Russian Telegram site took the number of Ukrainians "killed in action" ("16k-17.5k") and put those on the Russian ledger, while flipping the numbers on the Ukrainian side so they read "61k - 71.5k".