NGC certified professional exam — what does it actually cover?

I've been collecting coins seriously for about 12 years and I'm thinking about pursuing the NGC certified professional designation. I've been submitting coins for grading for years but I've never formally studied the grading standards, and I'm not sure if the certification is worth the investment for a serious hobbyist versus someone going professional.

From what I understand, the exam covers US coin grading standards, strike quality assessment, surface preservation, luster evaluation, and eye appeal — basically the same criteria NGC graders use internally. There's also a section on detecting cleaned coins and artificial toning. I've been doing my own grading for years but I'm probably off by half a point on average on key dates, which matters a lot when you're buying or selling at auction.

My main question is whether the study materials NGC provides are enough, or whether I should supplement with the ANA grading standards book and Photograde. Has anyone taken this exam recently and can say how closely the practice materials match what actually shows up? I'm also curious whether the certification helped you professionally — either in dealing rooms, auction houses, or as a dealer.