In the Final Paper, the problems of practical application of methods of investigation on links between profits and sales profitability as well as its importance and methodic aspects are analyzed. In order to establish the impact of the sales profitability and other factors that are inseparable from it on profits, Du Pont’s pyramidal analysis is performed in the Paper. It is proposed to use the methodics of flexible budget for a settlement of the problem of comparison of static indicators, because such methodics help to obtain more precise and comparable values. A considerable attention is paid to investigation and improvement of the link between the expenditure calculation systems and the analysis of profit-affecting factors. Applying the absorbing method of expenditure calculation, the analysis of links between expenses, volumes of sales and profits had been carried out. The investigation of supply and rational volumes of production on the base of the analysis helped to disclose the problems of the applicability of the method of investigation on marginal costs in practice, its complicated character and efficiency.