There is a line that was crossed in the ammount of extra charges that Wolf was not happy with, that's the customer's side of it. There was a limit to how little the vendor wanted to make on profit, thats the other side. All that happened is those two numbers conflicted.
To say that makes wolf a 'cheapass' is hardly fair. Not everyone has sold a company and owns millions of dollars. Oh, and beside that point, alot of people who do own millions of dollars only get there by counting every penny. Not my style of living but I really cannot agree that a customer should pay whatever the bill is everytime without question. 
i'm not calling anyone anything.
i know how i run my business. i check it out. i give you an estimate. you agree or not. if you agree, and approve the work, then i do the exact work on the estimate. if there's other stuff that comes up, i stop, and call ya.
what often happens, though, is that after the customer has agreed, he comes in, and tries to play games with me, hoping i'll back down, and lower the price.
i've been dealing with people trying that for about 10 years now. i see it comin before they get to do it to me.
i'll go back and re-read the original post, as i may have missed something. i also run an auto shop, not an aviation shop.
they are somewhat similar though, except it's much more expensive to be legally allowed to do major maintenance on aircraft. when i rebuild an engine, i'm the only one that has to look it over or approve it. i know that it's somewhat different in aviation.
in all things such as this, it's hard to say right or wrong. if he was given an estimate, and the final bill was within 10% or so of that estimate, then there really shouldn't be a problem....assuming the go-ahead was given for the work.
now, if he was told $1,000, gave the ok on the work, and the final bill was that 1500, then there is a serious problem.
just my opinions, and observations, from running an auto shop.....