I tried writing a small macro to do what you said and it does work, move the MPG, run the Macro and the FRO changes...Perfect!! So far so good! Saved it as a macropump and it sort of worked but as you say, very slow and erratic.
So, now we have proven the principle, how can we implement it in a Brain? I think the two main conditions for this are:
1) Needs to work based on the condition of an input pin.
2) FRO should not be allowed to go below zero
In the macro I could only get it to work by storing the MPG count to use as the reference for the next cycle, since we need to determine the change in MPG DRO. Can this be implemented in a brain?
The other way I could see it working is to trigger a Macro from another input pin, but how can you call a Macro from an input?
Cheers