Fey Template -1 NAC vs NAC Enhancement?

[Stephen Ede]

They Fey Template has "Armor Class: Reduce the creature’s natural armor, if any, by 1 (minimum of 0)."
What if a creature has no Natural Armour but has an Enhancement bonus from the Automatic Progression Unchained rules -
"At 8th level, the character gains a +1 enhancement bonus to natural armor. This bonus increases to +2 at 13th level, to +3 at 16th level, to +4 at 17th level, and to +5 at 18th level."

Are there rules covering this?
Does it look at the NAC, go no NAC so nothing lost, and then apply the Enhancement bonus?
Or Calculate the total NAC before penalties and then take the -1 NAC penalty?

[Claxon]

The rules don't cover this, but the progression granted by ABP is to replace the amulet of natural armor.

Which creates a distinction between your own natural armor, and a magical enhancement to natural armor.

Personally, I would think that the Fey template wouldn't have an effect on the bonus granted from ABP or the amulet.