The provisions of Articles VII through XIV governing open and selective tendering procedures need not apply in the following conditions, provided that limited tendering is not used with a view to avoiding maximum possible competition or in a manner which would constitute a means of discrimination among suppliers of other Parties or protection to domestic producers or suppliers: ... when additional construction services which were not included in the initial contract but which were within the objectives of the original tender documentation have, through unforeseeable circumstances, become necessary to complete the construction services described therein, and the entity need to award contracts for the additional construction services to the contractor carrying out the construction services concerned since the separation of the additional construction services from the initial contract would be difficult for technical or economic reasons and cause significant inconvenience to the entity. However, the total value of contracts awarded for the additional construction services may not exceed 50 per cent of the amount of the main contract.
