Any costs incurred by the Planning, Town or Zoning Appeals Boards for legal, engineering or other professional consultants or similar extraordinary expenses incurred in connection with the review of an application before such respective Board shall be estimated at the time of application or first appearance before such Board and deposited in escrow with the Town Clerk. Any actual balances due shall be paid by the applicant in advance of the decision of the respective Board. The applicant shall be entitled to copies of all invoices submitted to the Town for reimbursement, and such invoices shall be itemized and charged at the rates regularly charged to the Town (or municipalities generally) by the consultant. In addition, such fees shall be subject to any legal requirements or restrictions applicable to the types of applications and the methods of charging professional consultants fees then applicable.