Everything below is fictional. When this gets built for a real business, the rate table on the left reads from whatever price list or per-unit rates the business actually charges by, and the flag on the right runs against whatever invoicing or job-management system already exists, it does not require replacing it.
Customer: get a locked quote
Sample rate table
Staff: job desk & invoice-consistency guard
How this gets built for real
The rate table is illustrative. A real build uses the business's own published or internal per-unit rates, not these sample amounts, so the quote a customer sees is the business's real pricing, computed instead of guessed at over the phone.
The flag is a comparison, not a payment system. This demo compares a locked quote against a final invoice amount a staff member types in; a real build reads the final invoice number directly from whatever billing or job system the business already uses.
A flagged job still gets resolved, just visibly. The point isn't to forbid charging more than quoted (a change order is sometimes legitimate), it's to make sure that ever happens on purpose, with a reason on record, instead of silently.
See it built for a real business: Prime Time Window & Gutter Cleaning, T & L Septic Services, or Security Fence Company.