What I have seen at Costco is the Techron "ProGard" version, not the Concentrate. However, the quote I found below implies that a double dose of ProGard is equivalent to single dose of Concentrate. And at Costco prices, a double dose of ProGard will cost less and be just as effective as the Concentrate.
Quote:
Thank you for your inquiry. It has been forwarded to us here at Chevron
Fuels Technical Service.
The ProGard and Techron products contain the same chemical additive.
There is but one grade of the Techron product, while there are four
grades of Pro-Gard. The Pro-Gard products are "Clean-up", "Fuel Injector
Cleaner", "Fuel Injector Plus Intake Valve Cleaner", and "Gas
Treatment".
The ProGard products give lower, less effective concentrations. These
lower-concentration packages often sell for less. They have less "keep
clean" and "cleanup" properties. They are also not concentrated enough
to clean combustion chamber deposits. There are only subtle differences
amongst the Pro-Gard products, mostly having to do with concentration.
Techron Concentrate Fuel System Cleaner is the most concentrated and
will clean combustion chamber deposits. There is approximately 100% more
active ingredient in the Techron Concentrate than the Pro-Gard Fuel
Injector Cleaner. The active ingredient is Poly Ether Amine with a
solvent carrier.
A bottle of Techron Concentrate Fuel System Cleaner, when added to
gasoline according to the label instructions, results in an additive
concentration roughly 10 times stronger than the dose in Chevron
gasolines.
If you always used Chevron gasolines, you should be getting enough of a
dose of Techron such that you should not have to purchase the
Concentrate.