I've heard multiple instructors talk of best value evaluations on a commercial $100k service and I still don't get a clear answer.  Question is does the evaluation factors that will be listed in the procurement have to say what's more important when combined? If not can we just justify the award decision in our memo and detail was was more value to us when we dove into the evaluations?

What procedure are you using from the FAR (e.g. 8.4, 13, 15)?  You asked a similar question last month and last year. 

http://www.wifcon.com/discussion/index.php?/topic/3337-best-value-simplified-acquisition/#comment-29834

http://www.wifcon.com/discussion/index.php?/topic/3151-evaluating-for-gsa-bpas-and-orders/#comment-28111

If using the simplified acquisition procedures of Part 13, see FAR 13.106-1(a)(2).  That should answer your question.  Also, whatever criteria is listed in the solicitation (RFQ) must be strictly adhered to in evaluating quotes.  Also, see 13.106-2(b)(3) and 13.106-3(b)(3) regarding evaluation and documentation.  I would recommend not making the evaluation criteria and evaluation procedure unnecessarily burdensome. 

Someone may be confusing the requirements of Part 13 with that of 15.304(d).

A guiding principle of federal contracting is fairness. If your plan is to change the relative importance during evaluation you may run into trouble if your solicitation was misleading on how the evaluation would work. Is it required by FAR Part 13 - no per se, but the real answer is fact dependent and based on the contracting officer's actions. Read this from the GAO:

"...we are sensitive to the fact that the thrust of FAR parts 12 and 13 is to avoid the use of procedures that constrict and complicate the acquisition process, and that FAR §§ 12.602(a) and 13.106-1(a)(2) do not, on their face, limit a contracting officer's discretion to disclose, or not disclose, the relative weight of evaluation criteria in a commercial item procurement conducted using simplified procedures. Nonetheless, basic principles of fair play are a touchstone of the federal procurement system, and those principles bound even broad grants of agency discretion."

Read the full discussion on SAP here: http://www.wifcon.com/anal/analcomproc.htm

thecontractingguy - you need to be more specific on what procedure you're using or anticipating - your $100k commercial service could be acquired in a number of ways: via a Federal Supply Schedule IAW FAR Subpart 8.4, via the open market IAW FAR Part 13, via an IDIQ IAW FAR 16.505 (and the IDIQ's specific ordering procedures), etc.  Maybe the reason why you're not getting a clear answer is that you're not asking a clear question.