MW, I know WoFF will confirm successful arty spotting mission. And that's the thing. You could be doing barrel rolls instead of spotting artillery during this mission and WoFF will tell you the mission was successful. You have to use your judgment to determine if the mission was successful or not. In your case WoFF manager says mission was successful but your CO says it wasn't. What to do? Well, you apply the DiD Centenary Challenge (R) rule: if at least one target was destroyed by you or a member of your flight then the mission was successful.

"Take the cylinder out of my kidneys,
The connecting rod out of my brain, my brain,
From out of my arse take the camshaft,
And assemble the engine again."