User blog comment:Chad Pattan/Dear Nubee: It's Time To Clean Up The Cards./@comment-25751901-20150612122438/@comment-25435121-20150612142039

yeah, that is the main reason I almost never summon. The only time I do is for Step-up there I can usually get 2 UR on the last round, 1 Garunteed, and extra. I always laugh when they say "Increased Rate!" and no one even know what the old rate is to know if it really increased.

Again, Box summon is the only summon where you know your approximate rate: 1/77, then 1/76, etc. However, I can guarantee you that Nubee is not using the 1/77 rate. It is likely weighted so that the R and SR cards always have a higher rate of showing up.

For example of possible Box Summon weight distribution. Let's say they want to start off with the UR having a rate of 1/1000, and the SR having a rate of 20/1000. They will fill the Box with 1000 actual cards(of 77 distinct cards), one of which is the UR. Then for the SR, let's say there are 10 available in the box (I can't remember the exact number). This means that they will place 2 of each SR card in the box for a total of 20 SR chances. The remaining 979 cards are then all R cards. When you draw summon from the box, Nubee will pick a number between 1 and 1000, and give you the card that is in that slot, and remove ALL instances of the card from the 1000 card pool. So if you performed a Summon and got 1 SR card, the pool would now have 998 cards to choose from, and your SR rate changed from 20/1000 (2%) to 18/998 (1.8%). You have now made it harder to get an SR card.

Now, this is just one possible way of implementing the box summon, I have no idea if this is how Nubee really does it. But what it shows is that the raw number of R cards DOES NOT MATTER.

Just because you don't like a card doesn't mean other agree with you. I see no reason that they should retire cards.