Warranty claims!

You shouldn't need to barter with any supplier. If parts are faulty and cost you time to test and replace, then the manufacturer should be held accountable. What is presently happening is that the manufacturer is getting away with manufacturing cheaper and cheaper parts and when they go faulty they are laughing all the way to the bank because it costs them nothing, but you as a business if you had half a dozen faulty cars back after a few days and you had to pay a technician to diagnose and fix the customers cars, who are not paying again, then that wage bill will creep up and no income is generated for it because the manufacturer is laughing at you making good profit without expense.

See what I'm getting at!

Now if the supplier is creaming in on it then they have a second labour income for free as well!