I'm on S8 if it helps any!!

I'm not sure about the 0-255 you're on about is that to do with the 16 x 16 mapping points then??

Basically, I noticed that the min on time was set to 1200 microseconds - but on the fuel map I thought I was getting close to that and therefore not allowing me to adjust enough for it!! Turns out it's nowhere near it on idle but on overrun it gets close.