Even if it's less than people anticipated him getting, it's not like he's going to get like $1 million a year or something. No way it's a significant enough difference to affect their ability to sign Fielder either way.
They're not going to think "Well, that's $1-$2 million a year extra over the next six years we have that we didn't expect, let's go spend $25 million a year on Prince for eight years now."