Hey smile,
Thanks for the questions, and congrats on the 15-point improvement so far! That's great!
First, I think you've got plenty of time to gain points prior to June. You've already seen that big gains are possible, so it's just a matter of continuing to work with the right tools.
With that in mind, let me give you some more information about those Advanced courses. To start, I think someone with your background/familiarity is a great candidate for what the courses cover. That is, some people hear "advanced" and assume it means exclusively 170+ type scorers. But that's not necessarily the case at all! While those people can certainly benefit, the Advanced courses are also designed with test takers like you in mind: people who have worked through the full set (or at least the majority) of their PowerScore materials and are looking to continue adding to their repository of knowledge. The Advanced courses essentially continue the conversation(s) begun in class and in our books to go even further, exploring every conceptual wrinkle that appears on this test, and every subtle move employed by the test makers.
What that means is that, while you can obviously work through them at whatever pace you prefer (they're On Demand, so entirely customizable), most students find they can move fairly quickly. I'd say somewhere around 1.5 hours for every hour of recorded content, meaning roughly 30-35 hours for each 20+ hour course. Clearly that's a generalization and your needs/abilities may shift that time up or down a bit, but it's a good rule of thumb.
How they differ from the FL materials is both a matter of content and intent. Content-wise you'll find that they lean heavily in the direction of conceptual discussions, and rely less on lengthy problem sets. We do cover a good many questions/examples, but the majority of the discussion is on how things work and what the test makers are doing in various situations (and, of course, how to respond), rather than the repeated application you find in the FL course. The beauty of pairing an Advanced Course with the FL is that if you need further practice doing actual questions, the thousands of problems that you have from the FL should offer plenty of opportunity for that!
The other difference, as I mentioned, is intent. Put simply, we didn't design these courses to be all-inclusive like the FL course. Instead, we view these as complementary, a supplement and extension on what you've already learned and, ideally, mastered.
Finally, should you take both? I don't know. That decision depends on where you're struggling and why, and also the subjective value you derive from them. So, for example, if you find that your 158 is made up almost entirely of missed Reading Comp and LR questions, then there probably isn't a lot to be gained from the Advanced Games Course (literally, you don't have many Games points to gain in that scenario). From a value-standpoint, these courses simply aren't designed for everyone. Doing these without any PowerScore background, or still as a 130s scorer, probably isn't going to be as rewarding as they are for high scorers or experienced testers (like you!). So experiences can vary somewhat, depending on who you are as a test taker, and why it is that you continue to struggle in a section or with a concept: if you struggle with Grouping Games, say, because you haven't practiced them much, then the Advanced Games Course probably isn't the next step; but if that's a weak area because you still find the concept difficult, or still get tripped up frequently by common features, then the Advanced Games Course can help you address that trouble really effectively.
In any case, there's no need to commit to both up front! Choose the area where you feel you have a strong grasp of the fundamentals but also plenty of room left to improve, and start there. If you find that course useful, then as you near its completion consider the other course and its potential utility, and make your decision then.
I hope that helps to clear things up, and please let me know if you have additional questions!
Thanks!
Jon