Intensity problem with moving head

I have several MH 14 channel, set up as a User personality with intensity on channel 1. The light's dmx chart shows dmx values 0-50 as on full, 51 to 242 as strobe and 242-256 as on full. When I use the ETC slider it continues to strobe right up to max on the slider so it appears that the channel cant put out the full 100% to get the top dmx values - the lower values work as per DMX chart.

I know I can adjust the range of the slider but cant work out is this is for every light in the particular show or just the one that I adjust ? Alternatively have I set the home value incorrectly ?

Halp appreciated