If I have dealt with a person before I don't worry about waiting. Let me be clear about a few points...

I don't do very many sales (nor do I like to sell chips), I never deal in values with 3 zeros, somy opinion may not carry a lot of weight. As a buyer, I prefer to be trusted, but amnotoverly bothered by the seller wanting payment beforeshippingout (mostly because legally I bear responsibility for insuring payment arrives, seller has burden of getting item to me in a safe condition). One of my best friends waits for my payment before shipping, he trusts me, just always does it that way.

I think your feelings of consistency as buyer and seller is to be respected. I would be reluctant to trust a person I don't know if the values got above the range I normally deal in.