I mean the reason for adding and subtracting the various things from GNY to obtain household's disposable income
It's very difficult to know how/what to explain as I don't have a feel for the level of your understanding. Perhaps you could list exactly which factors that you don't understand and specify what you don't understand about its inclusion in household's disposable income?
Profits made by companies ultimately belong to shareholders, but if profits are retained by companies, rather than being paid as dividends, then they are not available to the shareholders (individuals) as disposable income.
