nestle: why do you say it makes 54 cups (3.375 gal) but product says it makes 53 servings of 1/4 cup each or 13.5 cups or 84% of a gal?

The ¼ cup serving is the dry mix. You add water to the milk which makes a cup. So, if there are 53 dry (¼ cup) servings, you will end up with 53 fluid cups after adding water. I hope this helps.

Where is this milk produced, please?

The formula can be either produced in Chile or Mexico. - Nestlé Consumer Engagement Center

description says 900 gms makes 7 liters, but here it states that 28 oz makes .88 gal (a little more than three qts)--so what is it really?

It's the small can. They charged the large can price though. Normally I pay $15-20 for the large size and $6-9 for a small one. Basically a scam by this seller.