Since it is so new, not many of us had a chance to really put it through multiple types of paint yet. Todd should be able to give a very good complete answer to this.
In theory, however, It should not cover up the metal flake at all. It is a color charged wax / sealant combination so it should actually make the flakes pop a bit.
Dodo Juice Blue Velvet and Purple Haze use the darker montan wax as well and they do not mute the metal flake in the paint. Due to this I really do not see an issue with the Black Ice having any ill affect on your flake.