maximize untility AND minimize disutility
I believe what you're getting at is a concept in economics called "Loss Aversion". It has been used quite extensively in recent economic research, especially in behavioral economics and finance. Another important key word here is "Prospect Theory", which encompasses loss aversion as well. 

The basic idea is that people suffer more from a loss of x\$ than they enjoy a gain of x\$ compared to a reference point. The utility function has a different (smaller in absolute value) slope when moving in a positive direction from the reference point than when moving in a negative direction. This is illustrated by the graph below (source: https://upload.wikimedia.org/wikipedia/commons/4/4e/Valuefun.jpg).



Under these conditions,  utility and disutility are different. Otherwise, maximizing untility or minimizing disutility is the same, as you mentioned. 

This insight goes back to Amos Tversky and Daniel Kahneman.Kahneman received the Nobel Prize in Economics in 2002 for this work.

A summary of the most important literature can be found for example here: http://loss-aversion.behaviouralfinance.net/