preset mobius rewards??

Been wondering for a while now. Are these and other event rewards time based? Just got 3 of 6 voids as a fire giants. We all see the same monsters being summoned as doubles frequently. Like those stupid frogs. Or are the lvl rewards grouped into very focused rewards with small chances to pick from higher group? Time based or group based?

i'd guess group based.

for each level boss a win gets you a random number.

let's say for each level there are a possibility of 400 monsters (since C's are not rewards) ... I'd suspect the random number generator is based on 5-10,000 A larger percentage will be for B's, a smaller percentage for A's, and a minuscule percentage for an AA

that how all "luck summons" are done in games. It's very easily coded into the game that way,