I don’t use the organizer, but I can tell you the breakdown of Rosetta Stone. Level 1 has 4 Units (I haven’t checked, but my guess is that the other levels will be similar). Each Unit has 4 Lessons. So that would give the 16 lessons you mentioned.
Each Lesson has a Core exercise that takes 20-30 minutes and then several smaller exercises (vocab, writing, reading, speaking, listening, etc.) that take 5 – 15 minutes and just reinforce the Core. Each lesson also does some review from previous lessons. You can set up different programs, depending on the student. The programs will have more or less reviews, depending on their purposes. So that would explain how someone has over 100 lessons listed.
What we do is that I just plan Rosetta Stone 3 times a week. My children spend about 15 minutes each time. So they complete either 1/2 of the core lesson, or one or two smaller exercises/reviews. We haven’t been super consistent (Spanish is something that gets dropped if we get busy), so DD7 is in the middle of Unit 3, after one year. I’ve been working through it as well and I’m almost done Level 1. I think if we did it consistently 3 times a week, we would have finished the level in a year. We’ll keep working over the summer and hopefully be ready to start level 2 in the fall.
If you buy the homeschool version, there are also review worksheets and activities that you can print out. We haven’t used those yet, although I plan to look over them this summer to decide if we want to implement them next year. At first glance, they look like they might be more appropriate for an older student, but I’m not sure about that yet. There is also an audio review that you can use, but so far I haven’t implemented that either.
Using the organizer, it might work to just plan 3 sessions per week, so you would get 108 lessons in a 36 week year (or more if you want to do it 4 or 5 days per week). Then just mark that sessions as done once 15 minutes has been completed, regardless of which actual exercises were done. Mind you, it’s been a couple of years since I did my trial of the organizer, so I’m no expert!
Hope that helps. Let me know if you need any more specifics that I could look up for you.