Does "amplifiedparts.com" qualify as a reputable seller? They do have an online store for tubes and other things. I had not personally heard of them before. I have bought my tubes from TubeDepot, and always felt I was getting what I paid for. Tubedepot.com gets $180 for the same set.
Also I see where you can get a matched quad of SED Winged C from Amazon for $157.00. The Seller? amplifiedparts.com. And that is the same price as on the amplifiedparts.com website. So I don't know that they are or are not reputable; I also don't know why they are offering what are supposed to be the same tubes, plus three more, for $108.80 instead of their usual $157.00
I'm thinking maybe they are factory seconds? Meaning good tubes that have something wrong with the cosmetics, like a defect in the painted markings. I just recently saw something online about that--I believe with SED tubes.
EDIT: YEP, Found It:
http://music-electronics-forum.com/t18805/
(It's from 2010, so may or may not have much to do with the present issue.)