Bushloc inner edge lines?

[Magnus Forsberg]

Is this desirable or should the primitives and the parts that use them be kept the way they are?

Could you please give an example of were it is wrong? Partnumber? New or old part?

If I understand you correct, I see no need to create two new prims.
It is always possible to remove stuff from an old prim, to a new prim, and then use that new prim inside the old prim, adding the moved stuff.