PN;
The 2-ounces of additional water for each ounce of IDY comes from the manufacturer’s directions, it was not a part of the calculation. When using ADY you should include 2 times the weight of ADY as part of the water used to hydrate the yeast in. This is the same as for IDY, but since we don’t usually pre-hydrate IDY the extra water is added to the dough along with the regular dough water. This water SHOULD be in addition to the regular dough water, but it seldom is, that’s why I said “if you want to do it by the books”.
Tom Lehmann/The Dough Doctor