Summon rates on MS is 8% for nat 4 and 0.5% for nat 5. So your nat 4 summon rate is 27/306 = 8.8% and 3/306 = 0.98% for nat 5s. You got lucky at the beginning but your still above average on your rates. Once you start hitting the point where you are getting dupes on blessings that's when you want to start picking up LD scrolls instead.
i think this blessing in this game, dev half rate of nat5 from 0.5% to 0.25% bcause it must give you 2 monster to choose. my 300 ms didn't give any nat5 too.
