Vegetable oils "OU-Mehadrin" standard

In Vegetable oil what would be considered Mehadrin?

What are the other standards available?

Mehadrin= Produced in an all kosher facility. Processed from the crush of the bean through the complete refining, processing, & packaging all in the same plant-That's a mehadrin product.

The Nature Valley brand "vegetable oil" (soybean) [not their other oils, e.g. corn] sold by Dollar General stores.
The Carlini brand "vegetable oil" (soybean) [not their other oils, e.g. corn] sold in the Aldis stores.
The Carlini & the Nature Valley brands are the MEHADRIN brands. BTW- Both are OU Mehadrin certified brands.

Other oils with a lower standard would include the ones processed in an AV plant (Animal/Vegetable), or transported by tank, tanker, rail car, etc for further processing & packaging.

The Heimish fall under this lower standard category. A certain heimish brand "special production". They took the processed oil from an OU facility, trucked it in an OU kashered tanker, bottled it in a facility with a heimish mashgiach and it became a Heimish "special production". The mashgiach was in the "HEIM" for production & came for the bottling.

Why would one pay a premium for the Heimish brand, when you could buy an OU oil with less transpotation kashrus issues? I give up!