A. A logbook will be kept on-site for each piece of equipment to be maintained by the Contractor. The logbook shall contain the date each quarterly maintenance was performed. B. The frequency of quarterly maintenance shall be no more than ninety (90) days between services, with the first service to be conducted within thirty (30) days of contract execution. C. Contractor shall schedule the date and time the service is to be performed with the CHP on-site contact one (1) week prior to service. Contractor will check in with CHP on-site contact upon arrival and check out when the work is completed. D. All invoices must be sent with the appropriate accompanying documents to the CHP onsite contact for approval. Invoices must be legible, provide the date of service, and must be itemized or they will be disputed. If there are any discrepancies on the invoice concerning hours worked, the CHP will refer to the sign-in sheet to confirm actual hours at the facility. Invoices not on pre-printed bill heads shall be signed by Contractor furnishing the service. E. The scope of work included in this contract will serve as a checklist for the maintenance services performed. Contractor will be required to bring the checklist each time the quarterly maintenance is performed. All items on the checklist will be checked off as performed. Upon completion, Contractor will provide the CHP on-site contact with the completed check list. The list will be signed and dated by both Contractor and the CHP on-site contact and filed in the appropriate logbook. Additionally, an extra copy shall be left with the CHP on-site contact. A copy of the list shall accompany the invoice prepared by Contractor for the quarterly maintenance.