How does my board decide loan wage percentage?

I just downloaded a user made update to have a look round and selected Sunderland. I checked the transfer list and Kaka was a realistic target for some reason. I approached about a loan deal and he was on 195k a week, I moved all my transfer money to wages and I was 350k under my wage budget yet could only offer 40 percent of the wage. I then bid the asking price and I was allowed to offer 115k a week plus 100k a goal and 100k a goal plus a 50 percent yearly increase he accepted and signed for Sunderland.

This just got me curious as to how the board decides how much you can contribute towards a loan?

I didn't continue the game as I want to play as Fulham instead. This also got me thinking of how the board would allow a contract of that size to go through, do you think they should limit things a bit more or do you think the current limits are fine and it is more down to us to control things? I doubt in real life Quinn and Short would allow a potential half million pound a week player to sign for Sunderland as allowing half the wages for a loan move would make much more financial sense.