i assume that we are speaking about "different BOM's"
Ie , you have a purchasing Bom, a product structure Bom, a Spare parts Bom, a Packaging Bom, a ....
That said, I think all companies have different ideas on what should be reported in their Boms.
I guess a MSM is a tool to manage multiple Boms side by side since most or many of the items are included but maybe differently structured.