What is the Costco stock number, I won't use the pump DEF. Not trashing the pump DEF, if I had a Tractor that took 15-50 gallons, then it makes since. If I stick with only one brand that is accessible just about anywhere, then Peak DEF works for me. I don't go through enough DEF to warrant stocking it. You can always find it on sale, and if not (like friday night) it's not that much more. I was at a shell/Green Valley Grocers station here in Vegas and went to pay for the 2.5 gallon bottle and it was $20.00, I asked the clerk about the price, we walked over to the shelf, and it was missplaced over a price of +12.99. I refused and went about pumping the fuel. When I get to a 1/2 tank of DEF, I start looking for Peak on sale, and the Costco price is a good price.
On a side note: My buddy's SIL used to purchase the cheap stuff (If I remember correct, Walmart.) until he had an issue that cost alot of money, FCA denied warranty due to contamination, he only buys Mopar now, whether or not it was the fault of the walmart DEF.