My observations of mine are just that. Just what I observe.
My Green Fuzzy guy has lived split and grown well in my lowest flow are for a long time. At one time one was nearly a foot across before splitting. A few Reds in the corners in high flow have thankfully been slow to spread and take over, yet Blues close by in a high flow are have expanded and spread like crazy. My Rics on the other hand seem to like a good flow, but not excessive like the Blue ones seem to love.
In other words mine of different types seem to behave differently according to location and type of Mushroom they are. All are in similar light exposure so that is not what is making the difference occur.