Why Mechanical Contractors Overpay Most on December Change Orders

December is a dangerous month for mechanical contractors, and the biggest threat isn’t labor shortages or equipment delays. It’s change orders. As projects get pushed toward end-of-year deadlines and customers demand last-minute adjustments, mechanical teams approve more changes in December than any other month. That surge creates the perfect storm: overruns, substitutions, and quiet pricing shifts that go unnoticed until the job is closed and the margin has already evaporated.

The core issue isn’t the change orders themselves. It’s the lack of verification during the rush. When teams are juggling multiple open jobs, coordinating subs, and trying to keep schedules intact, the review process becomes reactive. A price that doesn’t match the quoted amount. A substituted part that costs more than the original. A labor line that isn’t aligned with the PO. These mismatches rarely stand out when dozens of changes are happening at once.

And this is exactly where mechanical contractors lose the most money in December. The assumptions are simple: the supplier wouldn’t deviate from the quote, the substitution is equivalent, and the labor quantity must be correct if it aligns with the scope. But assumptions don’t protect margin. Verification does.

Matching purchase orders to invoices is the most reliable control mechanical teams can implement during high-volume periods. When an invoice lands without a corresponding PO, or when the amounts don’t match exactly, the error becomes impossible to ignore. Instead of approving changes based on memory or urgency, teams get a clear line-by-line comparison that exposes discrepancies instantly.

Mechanical teams don’t overpay in December because they’re inattentive. They overpay because workflow pressure wipes out visibility. The teams that protect their margins are the ones that slow the approval process just enough to confirm accuracy before money leaves the business. Five minutes of verification early saves thousands of dollars in overbilling later.

December will always push mechanical contractors to move quickly. But speed doesn’t have to come at the expense of profitability. A simple verification habit — POs matched to invoices — is the difference between protecting the bottom line and watching it disappear.

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