Genghis
On this occasion, you are mistaken. The Seneca, along with many other light twins such as the Baron have filler caps towards the tips of the wings, and wedge-shaped tanks that rapidly drain to the point where there is no fuel visible under the filler point.
After 1 hour's flight, a Baron is "empty" if you go by a visual inspection through the filler.
This makes dipping the tanks completely without value.
Charlie.