User blog comment:PYR0NY3H/Summoning Tips!/@comment-25275649-20150218095849

Major factor in this game is luck or the-will-of RNG. If RNG says "No SR and UR for you!" then be it is. But so far i've observed some of my comrades who happen to be on hiatus mode (for 1 month) and recently got back and guess what? He got UR on first try on Box Summon (Megaera to be exact). In the end this is just a hypothesis but you can try it yourself if you want.