In absence of clarification from the questioner, we'll answer generically.

Question 1:  When is a price matrix required when issuing a solicitation for

services?  When the acquisition team wants information in a certain format.

For example, when the team desires that a excel spreadsheet be populated to calculate the

total evaluated price (TEP) or if there is a government provided rate

schedule that needs to be populated for all the applicable contract periods.

The rates will be used to evaluate price based on scenarios during the

source selection evaluation phase and to price out future task orders

depending on the contract structure. The acquisition situation drives

whether or not a price matrix is required and the acquisition team drives

the structure of the matrix, i.e.  what information they want and in what

format they want it.

Question 2. Who is responsible for creating the price matrix? The

contracting officer with help from the price/cost analyst if there is one available.