The 7/12 or 3/12 rule is about cards "from all banks":

BofA's anti-churning policies: 2/3/4 (BofA cards), 3/12 or 7/12 (all banks)

How is it going to know about cards which aren't on your credit report and aren't from BofA? Obviously, it would count business cards that do appear on your credit report (such as from Cap One or Discover), and it could possibly count business cards from BofA internally (Chase doesn't, but that doesn't prove whether BofA does or not). But without going to the trouble of pulling multiple business credit reports when you're applying for a personal card (one business credit report doesn't show cards from all banks, the way personal credit reports do), I don't see how they would know about business cards from Chase, Amex, Citi, Barclays, US Bank, etc.

There's way fewer datapoints of BofA applications than Chase applications, so it's going to be hard to figure out exactly how BofA does these things (such as whether it counts its own business cards or not). That was figured out at Chase only after tons of datapoints with people who applied in cases where they definitely would over 5/24 if Chase counted its own business cards but definitely would be under 5/24 if Chase didn't count its own business cards (which required someone with at least 2 Chase business cards opened in the past 24 months). I doubt we'll ever get enough BofA datapoints to figure out fne-grained details like this, especially since BofA doesn't seem to be as consistent in its policy (3/12 for some, 7/12 for others as a starting point) as Chase (5/24 for everyone).