The SUL-1100 is too tall to fit inside the SUL-1300 with the 1300's lid seated firmly, even though the deep-dish lid of the SUL-1300 adds extra height to the pot's height.
When the SUL-1100 pot is placed inside the SUL-1300 pot, the edge of the lid for the SUL-1300 will not "seat" at all onto the top of the SUL-1300 and the 1300 lid ends up supported entirely by the top of the 1100.
I don't do metric, but the combined heights of the 1300's lid and pot (without seating the 1300 lid onto the pot) appears about identical to height of the 1100 pot/lid. The difference appears to be the additional height for the 1300 pot/lid due to the "thickness" (although very thin) of the bottoms of the 1300 lid and pot.
JRS