I quoted a price - say 6 thousand dollars, for the job. Then, when I billed it, I would bill for the full six thousand dollars, with the notation of 1/10 net 30

I quoted a price - say 6 thousand dollars, for the job. Then, when I billed it, I would bill for the full six thousand dollars, with the notation of 1/10 net 30 or sometimes 1/15 net 30 (since a few organizations had trouble getting checks out quickly, and wouldn't even try for the ten). So there was only a discount seen by the accounts payable people - and it was never discussed at any time. I don't know if anybody that I actually worked with even knew I was giving the discounts. They were just there to motivate quick payment. At any rate, they worked very well in real life. Never any problems. Just a matter of adding the notation at the top of the invoice.