On the PC ver. I opened the Advanced Armor perk i.e Plate and Scale armor but no new menu appears when blacksmithing. I have been to almost every forge I can think of and the menu remains the same. I opened Arcane and Glass and have the appropriate menus for those. Is this bugged?

The Skyrim Wiki has "plate and scale armor" listed with no pics? Yet to be added?

Interesting. That was the next perk I was going to pick up. Hoping to upgrade my elven armor.

I want to know what this does as well. I found steel plate gauntlets that were better than my normal steel ones... so does this mean you can make plate and scale version of certain metals? (Haven't really messed around much with blacksmithing yet).

I don't think they're new armor classes, they're new armor under old materials. I say this because I've seen plate and scale steel. So check under steel.

NOOOOOOBS........

Check "Steel" ...

Lol..

Check the 'Steel' section, I have scale armor listed there.

I have the perk and I know there's some under steel but i don't think there's any under elven. I haven't got any other perks in blacksmithing apart from those 3 so i can't see if there's any more.

Plate steel armor is under steel, there are several other new steel things to be made as well. I know from crafting my own set of exquisite plate steel.
There are many other things it unlocks.
Just check for them under the normal materials.
Its still made with steel you know.