Fader FX - Effect on/Effect Increase Macro

I'm hard at work on my first major and personalised .tsi and have a question. I've been trying to map the volume faders to Effect 1 on both FX Units - my mapping so far works as follows:

I have 'Modifier 1' mapped to the 'deck cue' buttons on the VCI, and deck cues have been moved to the 'deck effects' buttons.

When I hold down M1, it activates fader fx [not unlike Ean's mapping] and also changes the LOW EQ to the two pole filter.

I've mapped the Volume faders [when M1 is on] with a macro to turn ON Effect 1 and to Increase the Effect [with the fader set to INVERSE so decreasing the fader increases the effect - again like Eans]

So my problem - The modifer and macro both work, the fader turns on Effect 1 and begins to increase it, but at 50% it turns off the effect and won't increase beyond 50% of the effect.

Is there any way around this. I noticed Ean has his mapping set so that the effect on the faders is always set at 50% so it goes from 50% to 100%. How is this achieved?