MIDI velocity edits have no effect

I've been making some velocity changes to about 90% of the MIDI notes in a track using the standard Insert/Process Velocity effect. The first two changes worked, but when the notes were still too loud and I went back in to do it for a third time, I found that the changes weren't having any effect. Every change I've made has been reflected in the note properties, yet from my last attempt it's as if they all actually got louder, rather than softer, and no subsequent velocity change has had any effect on them at all. I've set them all to 1 just to see what would happen, and then to 100, but both times they all still sounded exactly the same. I've made the changes via track view, in the piano roll, I changed editor setting from clips to notes and did it in that view, but still no change with how the notes actually sound. I copied the notes from the initial track into a newly created empty track, but still velocity changes had no impact on how they sounded. I've tried both the 'Insert' and 'Process' commands, and I've made the changes by selecting the notes and also the entire track, but still nothing. As I said, after every change the new velocity is reflected in the note properties, the notes just don't sound any quieter. I don't wanna just do a quick and dirty volume reduction across the entire track coz that won't achieve the desired effect. I also don't wanna start from scratch coz the way I have it now is (aside from the velocity issue) exactly how I want it to sound.
 
Anyone have any thoughts or ideas that might help?
 
Cheers,
Matt

Midi velocity isn't for changing loudness.
An organ sound (probably) won't respond to velocity at all.
A synth patch may change filter settings, not loudness.
 
To change loudness, turn down the output level.