[El_Phil]

Oh of course you try, I wasn't saying you don't. And of course you try to over estimate the costs, that's bleedin' obvious. But it can't be done with any pretence of accuracy. You can't predict all the problems that will occur AND the frequency of them. Especially in computers were you can test for every combination of hardware and software. Hell potential software conflicts alone is a vast field. If your claiming companys work out all the possible problems before hand I think it's you who's being naive.

Now if you have no idea what the problems will be and how serious they are how do you work out the cost of it? Unless you just take an (educated) guess at the number of phone calls and go from there. Then hire less staff just to be on the safe side. So its a stabbed at guess based on what happened before, nothing worked out about it.