I'm confused as well with these 600 series processor from qualcomm but i get it this way. Think the snapdragon 625 as the base model. The 632 replaces 630, which is a successor of 626, which is a slightly overclocked 625. The 660 is a direct successor of 653, which (at that time) was positioned a little bit higher above 625 but way under 820. The 636 is a slightly detuned version of 660.
Judging by the paper specs, these new generation of 600 series should ranked 660>636>632>630, as the classification suggest. But if these benchmark are true then i don't really get why would qualcomm kill the easy way to understand brotherhood of 600 series.
Maybe these confusion was created to keep refreshing the product line even though no actual higher performance increase in 600 series processor is available, so a not tech-savvy buyer would only know that there is something new to get about. It's like intel keep refreshing their 14nm line. I do wish they avoid these practice in marketing their product, but even samsung's exynos 7 series lineup (7870,7885) and any mediatek's naming scheme is also confusing as well.