It's not just the numbers/letters that count, the arrangement matters, too. There's a lot of optional info that can be stuck in there. But as far as I know, date code is ALWAYS the last four digits in that row (first two digits week, second two digits year)- or three digits if tires were made before the year 2000.
I guess that's all by way of saying that the numbers you've posted don't make any more sense to me than they do to you!
I've heard of a few cases where the date code was actually on the other side of the tire- have you tried looking there?