FAR 8.405-2(d) Evaluation of level of effort and mix of labor

FAR 8.405-2(d) requires ordering activities to evaluate the "level of effort and mix of labor." The Advanced Technology Systems, Inc. case at GAO, B-296493.6, from Oct. 6, 2006, held that agencies had to evaluate for this when the pricing was in "hourly rates."

There are tasks on the GSA Schedule that are not priced at hourly rates for labor categories. For example, software maintenance is priced at a fixed rate by a period of time (e.g., a year) for X amount of dollars. Whether it takes 2 employees or 20 employees to provide that maintenance is of no consequence to the government. The price is a fixed-rate for the task.

So my question is, if an agency is soliciting off the GSA Schedule for a scope of work involving both services priced by task and services priced by hourly rates for labor categories, does FAR 8.405-2(d) require the agency to evaluate the "level of effort and mix of labor" for only the the hourly-rates portion of the work, or all of the work?

If it is all of the work, how would the agency evaluate for the "level of effort and mix of labor" for the work that is priced by task at a fixed-rate?