For Clarification and Usage
It is important to remember that the DEC is not designed to be applied to existing patches without minor tweaking. Existing patches have usually been EQ'd in an attempt as to minimize fizziness, and are usually not the best 'raw material' to get the most out of the device. That is why it is recommended either tweaking existing patches or building new ones from scratch with the DEC engaged. It is then you can truly compare your previous non-DEC patches with the new ones.
In new addition, you must treat the device as a new add-on to your rig, not a simple 'stomp' effect to be toggled on & off. It is more akin to changing guitar pickup or amps - there is always some minor tweaking expected for optimum or best results not to say it suppose to be instant holy grail sounding tone because its a very expensive pickup or AMP if you get what I mean,.
Just build your new patch with the DEC ON then later switch it OFF and you'll see the ugly darkside of digital world