तयोरुत्पन्नो नित्योत्पादिको लाभोत्पादिक इति व्ययः ॥ कZ_०२.६.२६ ॥
tayor utpanno nityotpādiko lābhotpādika iti vyayaḥ
What arises from those two (recurring income and profit) is termed nityotpādika (income-producing). Expenditure is that which is lābhotpādika (profit-producing).
They build a fiscal logic: classify routine inflows, measure periodic profit, and identify the sources and expenditures that generate those flows for sustainable finance.