Simon would have to confirm this...
but I believe that the standard Naked Advantage Power is not the best way to add an advantage to abilities that are already constant like a Characteristic. In the case of Characteristics the reason is there is already a specific method to do this - Characteristics purchased as a Power. The only possible issue is that when you check the box "Add Modifiers To Base Characteristic" it works both ways. Any Limitations like Cost End will apply to the base Characteristic as well.
I have added an example of this as well as an alternative Resistant Protection Power with some Limitations added.
9 Bone Armor: Naked Advantage: Resistant (+1/2) for up to 12 Active Points, Constant (+1/2) (9 Active Points) - END=0
6 Bone Armor (Compound Power): (Total: 6 Active Cost, 6 Real Cost) Resistant (+1/2) (3 Active Points) applied to PD (Characteristic purchased as a Power) (Real Cost: 3) plus Resistant (+1/2) (3 Active Points) applied to ED (Characteristic purchased as a Power) (Real Cost: 3) - END=0
12 Bone Armor: Resistant Protection (6 PD/6 ED) (18 Active Points); Costs Half Endurance (-1/4), Perceivable (-1/4) - END=1
sargothrax v2.hdc 32.28KB
Hope this helps.