I'm thinking he might have been a bit bigger in origins as well despite wanting to be bigger for this film.
Here's his quote actually from when darren was still attached:
"Darren said with the last one, 'Hey, you looked great, but you're so tall that in those long shots you looked kind of like Clint Eastwood, and that's not Wolverine. He said that Wolverine, in the comics, is powerful, stocky, you know, he's short and thick. So he said, 'I want you to go there, get bigger,” he revealed to the Los Angeles Times."
He was apparently in bulk up mode when the production was delayed and i guess he had to trim back down for les miz. Still good progress though coming from a trim down.