Having run a manufacturing plant, I can promise you that you want to give your production line employees as few subjective decisions to make as possible. They want clear guidelines to follow.
CAI's guideline was almost assuredly this: Transliterate the first two letters in the original SN to their Latin equivalent. Period. End of Story.
Not "do what you think will possibly work." It takes an employee much less time to simply follow guidelines than to evaluate each and every SN and decide what to do.
We in fact don't know that ATF didn't direct them to do that. Cyrillic letter is useless to the Feds.
It's simply as that, boys. CIA did the only logical and economical thing.
No, I don't, never have, and have never known anyone who worked for CAI. Yes, CAI has been a good company that has benefited C&R collectors and shooters more than any other company.
Y'all need to stop thinking that someone at CAI has the time to look at each and every one of the tens of thousands of Mosins they have imported so they can decide that they won't set their efficient system aside so that a rifle they will sell for $40 will be worth $50 to someone else.
Really, y'all CAI bashers need to get a grip on reality.