An accounting system for an income statement under absorption costing (full costing), with a means for identifying the break even point in a break-even chart, using a 45-degree line, defining .eta.=the net carryover manufacturing overhead applied in inventories, treating .eta. as an additive constant to the other constants in a conventional break-even chart and identifying the break-even point as the intersection between the variable cost line added on the constant line and the 45-degree line. The system further includes a means for identifying the individual break-even point for each individual income statement of manufacturing management accounting departments in the company aiming at the managed gross profit chart previously originated by the applicant; for disclosing the break-even charts for concerned company personnel over a computer information network; and for advisors' advising system to send said break even charts over the information network to company clients.