najprej metodološkega, saj je bilo treba po odklonu od ustrezne črke predpisa ESR upoštevati vsaj duh tega predpisa (z vključitvijo dveh ločenih dejavnosti); drugič pa praktičnega, saj bi morala merila, ki jih je bilo treba razviti, služiti kot natančen in primerljiv okvir za določitev, katera potrošnja znotraj enote se mora prikazati, da bi bila ta metoda izračuna proizvodnje izvedljiva.
first, a methodological one since, after deviating from the letter of the ESA rule, there was a need to follow it in spirit (by involving two separate activities); secondly, a practical one, since the criteria to be developed were to serve as a precise and comparable framework for defining which intra- unit consumption had to be recorded, to make this method of measuring output feasible.