I had a course savor subscription last year and took detailed notes on each chemistry video and when I look at the chad's videos website (at least) for gen chem the videos are longer but it would eventually lead to the part of the video where all the examples are identical to my notes from last year, so I'm assuming they are just longer videos. As of yesterday, Chad has another site for chemistry (not exactly DAT focused but chemistry and its a lot cheaper than course savor and I'm also scared the free website won't be free anymore)