Take Doc's advice and mix it yourself. In addition to the doubt about whether or not it's Michael Smith's formula, I would also like to know about the amidol. If it's Chinese in origin, you'll be really turned off to the whole experience. And then there's the outrageous price.
Artcraft Chemicals will sell you 1/2 lb. of English amidol for $105.00, which works out to about $0.50/gram. The other chemicals in Michael's formula can be purchased all over the place dirt cheap. (sodium sulfite, KBr, citric acid). At 8 grams / liter of amidol, your cost per liter of working solution is around $5.00 if you mix it yourself. Compare this to the Formulary's price.