You know those big electrolytic caps that keep killing antisparks (and causing sparks in the first place) they make sure the current through the battery does not spike as described.
The TOTAL voltage sag is higher on more cells in series BUT the sag PER CELL is the same regardless of configuration for the same power levels, so the excursion on each individual cell is the same.
Bottom line, higher s count configuration is always better, so long as your electronics can handle it.