Motor mooching is not trolling. Regular mooching is using the existing current to impart action. Motor mooching is either to slow you down in the current, meaning you are going backwards, sit in one place, or creating a current type of action where one doesn't much exist.
Trolling you are covering a lot of water. Motor mooching you are covering very little water or if you are it's at a snails pace. Motor mooching allows for radical changes in depth with every fish tail of the boat or putting the motor in and out of gear. You don't "troll" the kelp beds.