>>44268373/feh/ggot here, let me tell you how it works.
Whenever the summoning circle opens, the first thing the game does is assign a rarity for the each orb. From there, the game assigns a unit from that rarity then shows color depending on said unit. Assuming a 4 person regular banner, of the base 6% 5* rate, the focus 3% is split between the focus units making it 0.75% each. The remaining 3% is distributed among everyone else in the 5* pool. What feh offers is the opportunity to skip past undesirable colors, the rates themselves are NOT good. I've seen people get FGO levels of screwed.
