I believe this cant be done. It uses a default of true when a surface is provided.
The Rim Elevation (with Manhole types) is always the insertion point of the structure and is controlled by the surface level and the a adjustment value. As for the Sump this is controlled by the lowest in/out pipe and the specified sump depth. There should be two grips on the structure, one at the top (the surface adjustment grip) and one at the bottom (the Sump adjustment).This is as it is designed to work so otherwise to adjust the level you need to use the connected pipes.
So no you cant redefine the insertion easily without creating new parts. How are the blocks causing you issues? Try using display as boundary in profiles/sections in the structure style this works.
Mike Evans
Civil3D 2022 English
Windows 7 Professional 64-bit
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