Max for Hibbert is for less than a max for someone like Williams. Should be around $14 mil. No disrespect, but anyone who thinks Hibbert is worth only $8-10 is kidding themselves. Kid's only 25, is a true center who can pass, play great defense, is a stand-up guy, has worked on his game to improve it every year, and is 7'1". That player isn't available every year in free agency, and probably not once every three years. Putting him next to Aldridge gives them one of the best, if not the best, 4/5 pairing in basketball.
As I've posted in about 5 threads here, I'd have loved to have Hibbert next to KG. I think it would be the single best addition to the Celtics roster that was available in free agency. I still hope DA kicks the tires and figures out how to offer him $12/year to see if he'll accept it, in case he likes Boston more than Portland.
I'm not sure Indiana can match a max contract if George Hill also gets a big offer... they'd certainly have to pick between one or the other.