True, Amsoil agrees: http://www.amsoil.com/lit/databulletins/g1968.pdf
Gotta remember tho that the additive isn't necessarily just for reduced friction. The additives are sometimes also referred to as viscosity modifiers because they may be recommended for different purposes: Flow at high temps, flow at low temps, flow at high pressures, adhesion to meshed gears, ...
I don't know the purpose that Isuzu had in mind when they required the additive but it would appear that synthetic lubricants meet that need without the additive.