thanks for the clarification of the process.  I was not sure if mentioning during the pre-screening would be construed as making "an admission" or not.

If you are not asked about drug use outside the seven-year window before your polygraph interrogation (it is not just an interview), then no, it would not appear as an omission.

Your polygrapher will question you at length about various topics during the pre-test phase, and at this point you'll have the opportunity to discuss the full extent of your past marijuana use.

Note that if the agency you're applying with is either the CIA or NSA, you are likely to initially be accused of "having problems" (if not outright lying) with regard to one or more questions and to be scheduled for one or more "re-tests." This seems to be the standard operating procedure for these agencies.

If the the old use (10-11 years) will come out during the polygraph, is there someplace that I can disclose it prior to the interview?   

What I am concerned about is if it comes up for the first time during the interview, will that not appear like I ommitted it earlier?  On the other hand, the SF86 only asks for 7 years, would this type of information be volunteered there. 

I think during the lifestyle polygraph you will be asked about any illegal drug use during your entire life, and not just the 7-year window asked about on form SF-86.

I need to add, these intel agencies will be doing lifestyle polygraphs.

Do the polygraphs for the intel agencies look beyond the 7 year window that is on the SF86, or do the questions limit themselves to that time period only?

For example, I have not touched anything for well over 5 years now.  6 and 7 years ago I did MJ maybe 4-5 times.  9-10 years ago I did MJ maybe 50 times.  From what I understand, I would only report the incidents that were 6 and 7 years ago.  The earlier incidents would never come up?