If you take your C&A tinted specs off for a second you'll see that they're well within their rights to try and take the price down a bit. He's out for six months potentially, no way would/should they pay full price after that. I would expect Motherwell to do the exact same thing in their shoes.
There's been a lot of rage at Celtic from our fans over the past couple of weeks, the 'magnificent offer' and John Kennedy pish completely justified. Trying to reduce the price a bit isn't.