Incrementing a math channel

How do I increment a value  by a fixed amount when a condition is true? I do not want it to increment again until the condition is false then turns true again. 

I am trying to set a requested engine speed using a MACI channel. When I bump the throttle switch for less than 350 ms, I want to increase the channel by a 25 RPM increment. It seems that the simulation is adding 25 RPM to the channel on every cycle. I am getting several increments of 25 on each bump instead of 1 25 increment increase. 

If I hold the throttle input for more than 350 ms, I want to add 50 RPM every 250 ms to control to the throttle rate. I was trying to using a timer channel to increment the value by a fixed amount every 250 ms, but it seems this is happening faster than it should also.