Can one assign points to cost when using Tradeoff ? Can this be done without informing the bidders?

We our a contractor to USAID and our project is doing some construction work. When evaluating, the COP (Chief of Party)  wants to assign points to cost and what he is proposing is the following:

• Issue the RFP/RFQ using Tradeoff method and the evaluation criteria is and at that stage, no points are assigned to cost, the technical is evaluated based on past performance, personnel, etc.
• Then when the TEC determines the firms that are the most technically qualified, those firms move to the next stage and their cost is evaluated.
• Because this is construction, it is each line item, each material cost that is the most important part of determining cost reasonableness, not the total amount.
• So the evaluation committee, in order to determine price reasonableness, assigns points in order to determine cost reasonableness of each line item.

 Any thoughts if this can be done?