I totally get what you are saying. It would be great if each clutch would have the proper number of babies to show each possible mutation that the parents show or carry. But realistically, eggs don't hatch, some chicks die, etc. So mathmatical percentages don't match with what you actually see in the nest.
For example : Mystique and George are a pair who decided to surprise me with little ones. Mystique is a sf grey opaline; George is a green who it turns out carries blue and opaline. I could have gotten grey greens, greens, greys and blues, with some being opaline. Out of 6 fertile eggs (second clutch; first clutch never hatched), 4 hatched. I got one grey green, one green, one grey, and another grey! Would have been nice to get a blue, but it wasn't meant to be. Three are opaline, one is normal; I believe that is off the mathmatical percentage too. Stormy and Noah also had little ones. Stormy is sf greywing grey opaline, Noah is a green who carries blue and opaline. Both it turns out, carry pied. Out of eight fertile eggs, 7 hatched. I got two green opalines, two blue normals, a blue (normal) pied, a green (opaline?) pied, and a green normal. I can't tell if any are grey greens, but I got no greys with these guys. Lol, gotta love the odds