For example, $8M to business account (EIN) and $4M to personal account (SSN). No reason to believe activity is suspicious (he often exceeds $10M to business account, so it appears unlikely he is structuring to avoid reporting).

Anyway, the question is, this does require a CTR, even though the TINs are different, correct?

I had this situation and completed a CTR with the DBA business in Section A and the person in Section B. My situation was the same person was depositing the money, he was also the person in the DBA name, so it made sense to me to file. He was the beneficiary of all the funds deposited either in a business or personal account.

Yes a CTR is required, but LauraL's answer is not quite technically correct. You don't need any Section B - just two section A's.

This specific situation is described and answered in a Q&A. Refer to FIL 70-95 and scroll down to Question #22 (Example B):
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Example B: An individual deposits $5,000 in cash into his personal account and returns later in the day to deposit $6,000 in cash into his employer’s business account. Because the financial institution has knowledge that this individual has deposited $11,000 in one business day, it must file a CTR. Complete two Section A’s (one Section A on the individual, entering his ID in Item 14, and the other Section A on his employer’s business account, entering N/A in Item 14); in Section B check box d (Multiple Transactions) and box e (Conducted on Own Behalf) to indicate why Section B is left blank.
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David, just to clarify, this is not an employer's account - the depositor is the sole proprietor.

I don't see that this would change your statement about filing, but would you still complete two section "A'a"?

You could argue that the business and the individual are one, and that you only need one Section A. But you could also argue that filing two section A's provides the potential for two addresses (personal and business) and two TINs (if you use the EIN in the sole proprietorship info).

If you complete two section A's, put the individual's on the front of the form and check "completed on own behalf" in section B, leaving the rest of that section blank.

I haven't seen anything in writing from FinCEN indicating that either of these approached is wrong. If anyone points me to something official, I'll gladly reconsider.