Question: Prep 18

Sorry if this has been asked and can be a stupid question

Why is Prep 18(December 1992-that could have been Prep 7 as October 1992 is Prep 6) not following a chronological order? :question:

Is this prep test different from others in terms of difficulty? Any idea?

The December 1992 test was unreleased (like the Feb tests today) but was later released as a PT by the LSAC in 1995. That’s why it’s out of order.