I think they called it the 630 because they are planning to drop the 5XX range because lets face it the 5xx and 6xx ranges were so similar it's not worth having both the 630/635 can be the super low end cheap phone for people with not much money, then the 730 (hopefully coming soon) can be the Moto G competitor with 720p display, flash, 1GB RAM, 8MP camera etc then not sure what the 830 could be and then the 930 is the super high end top of the range incredible crazy quality premium device, then the 1030 can be the same as 930 but with super incredibly amazing camera and 1520 is just larger 930 with larger screen and bigger battery