I'm in agreement with Peter, the amount of yeast given (1%) is even correct for compressed yeast (CY).
While there are different types of instant dry yeast (IDY), one is for breads, rolls, pizza, etc. This one is typically packaged in a red colored package. The other form of IDY is designed specifically for high sugar products like pastries and is usually packaged in a gold colored package. The "high sugar" version is intended for use where the sugar level will exceed 18% of the flour weight BUT it has poor tolerance for salt. If the salt level exceeds 1% the yeast will ferment VERY SLOWLY so if you are making a high sugar product with a salt level much over 1% you are better off using the red packaged IDY but if you are making a high sugar product with a salt level of 1% or less, the gold packaged product might perform better. This is a carry over from the baking industry in Europe (where the IDY yeast brands originally came from) as it is a common practice in Europe to reduce the salt to very low levels when high sugar levels are used and vice-versa.
Tom Lehmann/The Dough Doctor