A preliminary estimate may change when the contractor measures the roof and examines access, details, and condition. The important question is whether the revision explains new information or simply replaces an earlier unsupported figure.
What to do next
Ask for a written comparison of changed assumptions and scope. Keep rough estimates clearly labeled in your records. Use the site-specific proposal as the basis for decisions while resolving any remaining exclusions before approval.
Related Perkins guidance
Contact Perkins Roofing to discuss your roof and the appropriate next step.