Boron is not used as ONE universal compound. So discussing the amount in any oil without the makeup of the different structures is kind of pointless.
"1.6.7Boron compounds have unique combination of tribological properties. In addition, they aregenerally believed to have little if any detrimental effect on either the machine components orthe environment [82]. Therefore, research on boron based additives has considerablyincreased within the last decade. Specifically, boron compounds have been extensivelystudied as boundary lubricating oil soluble additives, solid lubricants and surface coatings[83-86]. Oil soluble organoboron compounds are promising friction modifiers, corrosioninhibitors, antioxidants and effective antiwear additives [87-91].Boron compounds are capable of forming glassy structures in a manner similar to ZnDTP butwith different glass transition temperatures [92]. It is known that crystalline or amorphousboron, boron nitride and metal boride are very hard materials. Microindentationmeasurements on Rhenium boride (ReB2) indicated an average hardness of 48 GPa under theapplied load of 0.49 N. Scratch marks left on a diamond surface confirmed its superhardnature [93]. Hard iron boride (Fe2B) can be formed on the steel surfaces improving theirhardness [94, 95]. The hardness of crystalline boron is 30 GPa and amorphous boron thinfilms can also have hardness approaching that of crystalline boron [96].In a moisture-containing environment, surface oxide of boron (B2O3) is known to react withwater forming boric acid (H3BO3), which acts as a solid lubricant (Fig. 17). The lubricity ofboric acid has been attributed to its tendency to form a triclinic crystal structure made up ofatomic layers parallel to the basal plane. In each layer, the B, O and H atoms are closelypacked and bonded to each other with covalent bonds, while the layers are held together withweak van der Waals forces. The latter facilitates the layers to easily slide with respect to eachother providing lubricity in the system [97]."
11 kinds of Boron if you scroll down here.