Another problem with the powdered milk heter is that its source is from butter, and the exemption for butter only applies if the milk was intended from the start to be used only for butter so according to some, the issur of Cholov Akum was never relevant to this milk. However, if the cow was milked for drinking or unspecified purposes, that milk is immediately forbidden and does not lose its Cholov Akum status to become Kosher when it is churned into butter.
This is true of all our powdered milk today which is milked commercially.