Cos Ipswich are in the telly money, and Brum are 3rd tier. I believe the previous transfer record in that division was 3m
But FFP works differently in L1, I think there's a soft cap limiting you to only spending a certain percentage on wages but nothing on transfer fees.
Yes, they've paid a premium but if he gets them back into the Championship, and then well up the league in the Championship, it's worth it. He'll still have a high sell-on value too.
If you've got the opportunity to sign someone of his quality and can afford to do so. I don't think overpaying is a major issue. It's not like he's at the tail end of his career