If a custodian determines that a written request is excessively burdensome or broad, an additional reasonable period of time shall be allowed to comply with the request. The custodian shall provide written notification to the requester within fifteen days of receipt of the request that additional time will be needed to respond to the written request. The requester may deem the request denied and may pursue the remedies available pursuant to the Inspection of Public Records Act if the custodian does not permit the records to be inspected in a reasonable period of time.