If the roof of your home is damaged due to hail the insurance company is obligated under a replacement cost policy to return you to the condition you were prior to the loss. In other words, the insurance company has to pay for replacing the damaged roof. If the insurance company has already paid a partial claim previously, it is not obligated to pay the same claim again and may deduct the amount you received for previous damages, even if you did not repair those damages. In other words, the company is not obligated to pay for the same roof twice if you chose not to repair the prior damage.
If your home received hail damage, some policy language permits the insurance company to pay only a portion of the estimate. Certain policy language permits this until all the repairs are complete. Once the repairs are complete, a final bill should be submitted to your insurance company and they will pay you the remainder of the claim. However, most policies also request the repairs be completed within the time allowed in your policy.