The Planning Board may, as a condition of any approval, require the applicant to install a public improvement of greater size or capacity than required to service the applicant's project. Such approval shall provide that the applicant is entitled to reimbursement to a maximum amount equal to the difference between the amount of such cost and expense by the developer and the developer's pro rata share of the cost of such improvement. In such a case, the Township shall determine all property specially benefited by the improvement and of the value of the special benefit to each such property in accordance with the provision set forth hereinabove. The Township shall then assess all properties, other than the property of the developer, specially benefiting from installation of any off-tract improvement in a manner similar to that for local improvements. The Township may, in its sole discretion, pay any remaining balance to the developer rather than assess all other properties specifically benefiting from the installation of the off-tract improvement. Principal amounts received by the Township from such assessments, together with interest from property owners who have elected to pay for said assessments over a period of years, shall be credited to the real estate account of the developer's property. In the case where there has been an apportionment of cost against the Township for the required off-tract improvement, then the Township shall pay its portion of costs of the developer not more than four months after the completed improvements have been approved by the Township Engineer. In the event of any default in payment of an assessment levied by the Township as set forth hereinabove, then the Township shall exercise its remedies as elsewhere provided; and, if thereafter the balance of principal and interest due upon the subject assessment has not been fully satisfied by payment to the Township and credit thereof given to the real estate account of the developer's property, then the Township shall forthwith pay said balance remaining due to the developer, or his successor in interest.