I can agree with you on further discussing with the contractor on-site. However I do not believe that this is a precedence in my case.
As I am merely asking to forgo the paint and primer provided, to offset the labour interior and exterior (Extended portion inclusive).
To count by square meter/ space for the paint job (What is the original space agreed upon for a type B house?), I think it will be best that I talk to the contractor on-site.
As he can assess the area and decide upon.
Please re-consider, kindly pass on my views to the contractor as well.
And let me know of your decision, which will allow me to discuss with the contractor on-site amicably.