At 2-3ml/gal, it's hard to believe it's supplying much of anything. Especially $7 worth of anything.
It would be interesting if you did a side-by-side with another foliar product. In the other thread you replied to a post that contained two recipes. (That's why I thought you were referring to a recipe you found here.). Have you thought about trying one of those?
For example, it could be just the water improving humidity around the plant, or creating a temperature drop due to evaporation. Or, stimulating the stomata. Or, if a touch of SuperThrive didn't do something.
I'm skeptical of stuff like this because I could sell 20g of dolmite powder on eBay, call it "Dapper Dust: a blend of proprietary earth dust to make your soil more hospitable for root development. Add just 2g per gallon of soil." I guarantee I'd sell 10 of those for $60 (+ shipping) in 30 days. Before long there would be people on forums saying "this stuff works! I saw it with my own eyes. If it improves my yield by 5% it's worth it!"