When creating a new, empty material, with just 3 nodes, I am getting very high instruction counts. Compare this newly created material, which the engine reports a instruction count of 754.
By glancing at it i can automatically tell this is due to forward rendering. Despite the instruction count being so high, you will have better performance in forward, but you have to manually turn on things like full reflect quality. Deffered is the normal pick for pc and forward is the normal pick for VR, i think mobile uses a custom version of forward.