Break-even's own numbers become profit's inputs
The break-even example used a ₹250 price per unit and a ₹150 variable cost per unit, reaching break-even at 5,000 units. Feeding that same ₹150 "cost" and ₹250 "selling price" into the real profit formula gives a per-unit profit of ₹100 — identical to the contribution margin, because they're the same subtraction under different names.
Below break-even, that ₹100 per unit only offsets fixed costs
Every unit sold before reaching the 5,000-unit break-even point earns the same ₹100 contribution margin, but none of it is profit yet — it's paying down the ₹5,00,000 in fixed costs that haven't been covered.
A real example past break-even: 5,500 units sold
Selling 500 units beyond the 5,000-unit break-even point — 5,500 total — means those 500 extra units have no more fixed costs left to cover. Multiplying the real ₹100 per-unit profit by the real 500 extra units gives ₹50,000 in genuine profit.
Why this chain is exact, not approximate
Contribution margin (from the break-even formula) and per-unit profit (from the profit formula) are mathematically the same quantity — price minus per-unit cost — calculated two different ways for two different purposes. Once fixed costs are fully covered at the break-even point, every additional unit's contribution margin converts directly into profit with no further deductions.