A flat extra letter is the carrier's written notice describing the amount, duration, and reason for flat extra charge. It specifies the per-thousand cost, the time period applied, and any conditions for reconsideration. The letter helps clients understand pricing, plan cash flow, and anticipate when the charge might be reviewed for removal if the hazard abates or documentation improves.

After issue, advisors review the flat extra letter so clients understand the added cost and duration. Follow-up dates are set to request removal when documentation shows the hazard has ended or improved.