Can rates be changed up or down in increments?

Or maybe the same question in a different way - can a virtual channel output be used as the scale in a mixer?
The application is I want to be able to set the rates on a small quad and vary it in say 5% increments between 75 and 100 using trim switches to bump it up or down. Is this possible?

Use a mixer with a MUX of multiply, with the channel you want to use as the scale as the SRC for the mixer. That will scale the output of the previous mixer by the value of this mixer. If you have an analog input, you can use it to dial a scale value.

Thanks for the quick reply! Since I type out the instructions for dummies like me for future reference, this is what I did to follow your instructions, and it works

Go to TRIMS
Remove the wanted trim switches from whatever they are assigned to and assign
them to Virt2 (or other free virtual channel) with a step of 5. Step size 5 will
increase/decrease rates by 5% with each trim click.

Go to MIXER
Go to Virt2 and set:
Mixer - simple
SRC - Virt2
Curve 1-to-1
Scale 0
Offset 75 (offset 75 sets the centre position of the trims to 75% rates)

Now go to the channels in the mixer that you want to have the variable rates on, in
this case ELE and AIL, and set:
Mixer - complex
Mixers - 2
On page 1 set:
Switch - none
Mux - replace
SRC AIL (or ELE)
Curve 1-to-1
Scale 100
Offset 0
No trim
Now go back to the top and set page = 2 and the following:
switch - none
mux - mult
SRC Virt2
Curve 1-to-1
Scale 100
Offset 0
No trim

The only minor problem I have is I can't figure out how to limit the max and min values of virt2. I can limit the max value of each AIL/ELE channel which is good enough for my purposes flying 35gm quads, but for larger aircraft there could be safety implications. Thanks again for your help!