Lisa,
I apologize for missing your question on the board the last time around! I just responded to your email question today, because Julie popped in to talk to me about your email. I happened to be on the board, posting our first sneak peek for US2 and noticed your post here. So I have included my response below, so our other board readers can read it too.

I hope this helps clear up any confusion.
To refresh my memory, I have pulled up the thread which you excerpted in your email. The excerpt was as follows:
Tabitha,
I just wanted to pop-in and mention that you can award a full credit for the history in MTMM.

At the time I wrote the older thread on beefing up MTMM, the MTMM guide was brand new. Since we were not fully into writing the high school guides at that point, nor had I gone far enough through high school with my own son to truly know what could be awarded as high school credit, we were erring on the very cautious side with our advice on how to claim high school credit.
The thread which contained the excerpt is linked below for your reference as well.
Link:
viewtopic.php?f=6&t=16623&p=116946
In the excerpt you included in your email, which I've also included on the board post here, I was responding to Tabitha's reference to an old post of mine about awarding credit for MTMM that included the following comment:
Going by Carrie's info in the various beef-up posts, you need to combine histories from Rev to Rev and MTMM to be able to get a full credit in American History. My dd skipped the Rev to Rev guide, so only had one part of the history.
In that context, you can see a bit better what I was intending to say with the part you quoted. I can see where it can get confusing! I didn't mention the extensions in my response in the thread (linked above). The question about extensions was actually asked later in the thread, and I never got back to respond. Sorry about that!
My earlier advice quoted by Tabitha above was when I had first written MTMM (and we had not committed to writing high school guides, so we were still navigating what equalled a credit.) I hadn't even graduated my own oldest son at that point, so we were erring on the side of caution with the credit counting. Now that I am coming to the end of the high school guide writing process, and I have graduated one son and will have another who is a senior next year, we are well aware of what constitutes a credit.

I can easily see now that you can award a full credit for history in MTMM for your high school student, but we are intending that your high school student is using the extensions (unless the student is dyslexic or really struggles with reading). The extensions are really needed for high school level work. High school students could omit the Basic Package if desired.
Hope that helps to clarify! Thanks for your patience in hearing back from us.
Blessings,
Carrie