These rates are based on the game first picking 1 of 4 "rarity" catagories (3☆, 4☆, 5☆, 5☆ Focus) based on the displayed appearance rates, then selecting a unit from that rarity at random. All 5 units are determined at the start of a session. The color is only a clue as to what has already been chosen. Because of this, the summoning rates per color can vary widely since certain colors may be more or less likely to be 5☆ units depending on the banner and summoning pools. This is accurate to the best of my knowledge and is consistent with in-game summoning details.fehmeta.com is not affiliated with Inteligent Systems, Nintendo, or Fire Emblem.