Hi,
This is expected. We have 3 extra drawcalls regardless the number of lights for writing/clearing the stencil values. Then for each light we have 3 drawcalls instead of 1 (one for each type of tile. The number of drawcall is not a good metric, as these 3 drawcalls allow us to save some GPU time by using faster shader where it matters.
I hope this helps.
Cheers,
/Charles.