You are right. Only in a zero-interest-rate environment are they "equivalent" WRT NPV. If you can safely get high returns, then you have to discount them.
They are equivalent NPV wise only when the cost of capital is 25%. Cost of capital is a fuzzy concept and different folks have different numbers based on all kinds of things (despite the precise numbers put in spreadsheets). From a practical perspective they will almost never be NPV equivalent.