All depends on if he's billing the client for a 3000' roll or the 250' that were used.
If you say 3000, it's padding the bill. It's stealing from that client to generate a 90% surplus of material.
I know I said I was going to leave this thread alone, but I can't.
You are touching on the differences between a lump sum contract and a time and material contract here. I will not go into time and material contracts, because many (not necessarily you) on this site can't even comprehend a basic lump sum contract.
You bill the client for a finished product in a lump sum bid. You do not bill for time and material in a lump sum bid.
Lets say I was going to build you a finished 8x10 shed for $2500 with a complete set of specs and finishes specified by you. In the contract, it would read that I provide all material and labor necessary to complete the shed to your specs.
I could order 5 bunkers of 2x4s, ten stacks of 5/8 OSB, 20 squares of shingles, and 500 lbs of various screws/nails while I built your shed so I could get good discounts on supplies I know I will use in the future. I would obviously not use all that material to build your shed, it just happens that I was low on stock, so I ordered my materials in the most economical way I could from my supplier.
Let's say I even ordered 500 ft of 2 inch steel pipe while I was working on your shed, and I didn't actually need any of it for your shed. I just happened to order it while ordering materials for my stock that your shed will be built out of.
When the shed is done and you, as the owner, sign off on the finished product as meeting your specs that we originally agreed on, then I get my $2500, and you get your shed completed to your specs.
You do not get all of my material stock that I happened to order while building your shed. It doesnt matter if I used some of the material on your project(2x4s OSB, fasteners, shingles), or not (steel pipe), you get none of it other than what was used in your shed. In fact, my materials that I happened to buy while building your shed are worth more and cost me more than your entire shed. You do not get those materals as a client. That is not how a lump sum bid works. You get a completed shed built to your specs.
I don't know how to explain this any better over the Internet. This paragraph is a general statement, not necessarily aimed at you in particular. If you guys really care to know the how's and why's of construction contracts, then go to your local library and rent a book on construction contracting. It is abundantly clear that there are several on this site that have no clue how construction contracting works.