In recent years, the GMAT has been trying hard to become more “relevant” to business school. So, a decade ago, its arguments were just slightly dumbed down versions of the LSAT arguments. Now, some of their arguments (but by no means all, see the first worked example for a classic one) have a more “business decision” feel to them. These questions fit less cleanly into the basic structures of the question type, though at root, the rules are the same. However, to smash these questions, you need to have a stronger intuition about how these questions work so that you can apply the rules more flexibly.
As a consequence, I actually recommend to GMAT studiers that you go buy some LSAT tests — they sell individual tests, which might be enough, or books of 10 tests, which, if this stuff is hard for you right now, might be a good investment. These questions are good for building your foundation for two reasons: they have very transparent, predictable structures, and the types of logic they use can, on harder questions, be more sophisticated than what you will see on the GMAT. This builds extra capacity and good intuition. Then you can go work on the GMAT questions with a much stronger foundation.