I get all that, that you will pay more..but..
You are the guy selling him parts at full nut everyday..
Then when he has something for you..you lowball him..
..now if you were him, how would you feel about the guy making the offer.. What would your opinion of him, now be?
Think of it as being a prospecter. Do you want to return to the mine, again and again.
Or carry out what you can once, and return to a CLOSED.. Door..