Per preset.  you have to do a save for the new output setting to hold.  Also I sort of explained the process a little wrong.  Here is the correct way:

Output Level Control

Factor Pedals now gives you the ability to individually adjust each Preset’s Output Level.

In PLAY Mode, holding down the Left Footswitch for 2 seconds from Bypass state puts the unit into Active and also puts the unit into Preset O/P Level Adjust Mode. While the 
footswitch is pressed and held the display will show “OP 0dB” (default). While continuing to hold the footswitch down you can optionally turn the Encoder Knob to adjust Preset Output Level from –20dB to +6dB in 1dB increments. Preset must be saved or this adjustment will be lost when another Preset is loaded. (Preset Level Adjust Mode functions the same way in BANK Mode by pressing and holding the Left or Middle Footswitch from Bypass state.)