FX attribute - random


since i played today again a bit with Effects, i asked myself what is 'Random Rate' and 'Random Groupping' doing?

1. If i use {Randome Groupping} i seems the grouping could be like offset random, there are sometimes blocks of channels. Right?

2. But furthermore i realized that something with the Rate(?) will happen? Sometimes the Channels will pop up in notime or hold for a randome time.

3. I did a Trail of 40%(absolute FX; step1 on, step2 off), to have a nearly single dot that walks over my selection. If i combine {Randome Groupping} with it, it will happen that a lot of OFF states are been seen.

Means, the FX is mostly dark. And know comes the big Questionmark... Why?

4. If i use the same FX and Trail as in 3. and use {Randome Rate}, it seems that on a certain point the rate drops to 0, the channel will be jumped over and the next channel starts.

That resultes in the fact that i end up having a increasing amount of different channels, with a randome rate fading, over my selection where there shouldn't be more than 1(or to be more presize 3 because of the Trail).

Is this on purpose?