(iii)Retention at the percentage stated in Appendix A shall be withheld by the Employer as security for the proper performance of the Contract Works. Fifty percent of the retention shall be released to the Contractor upon issuance of the Practical Completion Certificate under Clause 15. The balance amount of ther retention will be released at the end of the Contractor’s defects liability obligations and issuance of the Certificate of Completion under Clause 15.