Not true..
You are the one using the CCR form data as your basis for determining business structure.
Every declaration of Global Detector says it is a sole proprietorship. CCR, USPTO by Jim Dahl about trademarks, local business listings, ..
Have you found one registration or declaration that says otherwise? NO.
Some unknown, un-named rep says subsidiary.
I don't think so.
So, have you given up on a subsidiary also being a sole proprietorship and agree IT CAN NOT?