Hi Moshe,
Thanks for the question. In the four in-class tests we use, there are experimental sections. However, for the non-in-class tests, we don't put experimental sections in, for several different reasons:
1. Not everyone uses the other tests as full practice tests. Some people take them as section challenges, half tests, general homework, etc.
2. Some people like to use certain tests as full practice tests, and if we happened to use that particular test as the source for experimental sections, they could couldn't do that.
So, instead, we provide the tests as they are released by Law Services--in their complete form.
As you suspected, the solution is an easy one: use a section from one of the other tests as your experimental (this works regardless of whether you go for a regular 5 section test, or go for an "overdrive" scenario where you do 6 sections at once). It actually doesn't matter which test you choose for the experimental, but I'd suggest using one of the older exams on the list.
Is there an issue with knowing which section is experimental? I definitely don't think so. On the real exam, you don't know which sections are real or experimental, but as I explain here (
http://www.powerscore.com/lsat/help/experimental.cfm), experimental sections are used on future tests, so they are as "real" as a scored section (especially since they will be used on a future test as a scored section).
When taking a practice test and you encounter an experimental that you know doesn't count, treat it as scored and do your best. Then, after you have taken four different practice exams and used the four sections from that test, total your scores on the "experimentals" and you have a fifth practice test result.
If knowing which one isn't part of the test really bothers you, the best approach is to print out several exams, note which test each section is from on the back, and then shuffle the extra section into the exam you are taking. You'll see a double of a particular section (two section "1s," or two section "2s," etc), but you won't know which one of the two "counts."
Please let me know if that helps. Thanks!