You Compare Nominal to Nominal/Real to Real, EXCEPT for Net Working Cap?

Is it true that I vaguely remember reading that you can calculate balance sheet info comparing either nominal rates to nominal rates, or real rates to real rates, except net working capital investment, which must be calculated in real rates? I am asking because I don’t remember where I read it in the curriculum…anyone know what I’m talking about?

Reading 40: Valuation in Emerging Markets

In real terms, only net working capital and tax expenses have to be calculated in nominal term first and then converted in real terms by dividing them by the inflation index.