The cheapest total is not necessarily the cheapest scope. Quantity and inclusion checks help expose when two subcontractors are pricing different jobs.
Before comparing totals, confirm that each quote covers the same measurable work. Compare quantities, drawing references, inclusions, exclusions and obvious interfaces. If one roofer includes flashings and another does not, the headline totals are not comparable.
Dividing the quoted value by a common measured quantity can reveal significant rate differences. It does not replace scope review, but it helps identify which quote deserves a closer look.
If the subcontractor's quantity is materially different from your independent take-off, investigate the reason. The issue may be a genuine interpretation difference, waste allowance, missing scope or measurement error. You learn more from the reason than from simply choosing the lower total.
An exclusion does not make cost disappear. If the work is required, either another package must carry it or the builder needs a remaining allowance. This is why quote comparison should feed directly into the project budget and cost-to-complete forecast.