never flown a Seminole myself but I recall an friend who instructed on it commenting that it had greater endurance if you shut down one engine after take-off (presumably at cruising level) than using both.
All light piston twins have greater range
and endurance on one engine, than at normal cruise on two engines - because two engine normal cruise speed is well above the most efficient speed, whilst single engine speeds are very close to it.
... of course slowing to best range speed with both engines running is more efficient than doing so with just one running.
