Some parts' meshes by default are set into expanded state (e.g. Drill-O-Matic). It affects (de)attach pointer and volume checks.

You can take advantage of the IMultipleDragCube interface to solve this.
This is implemented on most of the stock modules that have an extended/retracted state.
IMultipleDragCube.AssumeDragCubePosition(string name) will put the part (ideally the prefab) in a specific state, animation/model wise.
It also is implemented on ModulePartVariants, to set the part into each variant configuration (by providing the variant name).

IMultipleDragCube.GetDragCubeNames() can be used to get the strings to be passed as a parameter, for most modules, this is a static array.

Good to know. Thanks!