If MEP renewal counts for SEP then great, that will save some money but I fear the hour has to be in the same class of aircraft.
So if you had an SET or a Single engine sea class rating you would need an hour with an instructor or a proficiency check in each class.
Think about the people who spend all of their flying time in Jet Provosts then have to get into a 152 for a hour with an instructor to keep the licence current.
Rustles' point about the PFL is a valid one but heres a thought, why not do a PFL in the twin renewal with both engines idling? Could that not then count as the SEP renewal?