Sorry I wasn't the one to rip these, but the guy who did said that first 5 volumes came from amazon.jp and this one from dlsite, they have different DRMs imposed on manga viewing and thus the quality differs, the main problem is that DLsite is banned by credit card companies, so you can't purchase from there without jumping through hoops like buying yen and losing money to exchange rate, also DRM for manga on dlsite cannot be automatically circumvented, so he extracted every page manually, you can understand why he'd prefer to not bother with dlsite. If somebody went to the trouble to rip other volumes from dlsite, it would be great but for now it's the best quality we can have, sorry to disappoint. I think you can find every chapter in the magazine Ananga Ranga anyway, so it's not like there's no choice.