Relevant text (that I found):
An invisible but tangible field of force surrounds the subject of a mage armor spell, providing a +4 armor bonus to AC.
Unlike mundane armor, mage armor entails no armor check penalty, arcane spell failure chance, or speed reduction. Since mage armor is made of force, incorporeal creatures can’t bypass it the way they do normal armor.
Armor/Shield Bonus: Each type of armor grants an armor bonus to AC, while shields grant a shield bonus to AC. The armor bonus from a suit of armor doesn’t stack with other effects or items that grant an armor bonus. Similarly, the shield bonus from a shield doesn’t stack with other effects that grant a shield bonus.
In general, magic armor protects the wearer to a greater extent than non-magical armor. Magic Armor bonuses are enhancement bonuses, never rise above +5, and stack with regular armor bonuses (and with shield and magic shield enhancement bonuses). All magic armor is also masterwork armor, reducing armor check penalties by 1.
In addition to an enhancement bonus, armor may have special abilities . Special abilities usually count as additional bonuses for determining the market value of an item, but do not improve AC. A suit of armor cannot have an effective bonus (enhancement plus special ability bonus equivalents, including those from character abilities and spells) higher than +10. A suit of armor with a special ability must also have at least a +1 enhancement bonus.
Opinion:
I've always seen it ruled as no, you either have Mage Armor or your +1 Leather and not that it becomes, effectively, +1 Mage Armor. Is this correct, or have I been ruling and playing with this wrong?
There is no such thing as an enhancement bonus to you AC. An enhancement bonus instead increases the armor bonus of the armor it is placed on.
+1 leather armor does not give a +1 enhancement and +2 armor bonus to AC. It gives a +3 armor bonus to AC. The enhancement bonus does not improve your AC. It improves the armor, which then improves your AC.
You're correct. An enhancement bonus isn't a free-floating thing (like deflection or dodge). It only applies to the specific thing it's attached to, increasing its bonus. +1 leather armor doesn't provide +2 armor and +1 enhancement, it provides +3 armor. I can't find the general quote but the specific quote on armor is: "Enhancement Bonuses: Enhancement bonuses apply to your armor to increase the armor bonus it provides."
What page can I find this on? (And thank you for giving quotes, as that helps more than just opinions, as that's all I had before :P)
Edit: Found this on d20pfsrd
An enhancement bonus represents an increase in the sturdiness and/or effectiveness of armor or natural armor, or the effectiveness of a weapon, or a general bonus to an ability score. Multiple enhancement bonuses on the same object (in the case of armor and weapons), creature (in the case of natural armor), or ability score do not stack. Only the highest enhancement bonus applies. Since enhancement bonuses to armor or natural armor effectively increase the armor or natural armor’s bonus to AC, they don’t apply against touch attacks.
You're correct. An enhancement bonus isn't a free-floating thing (like deflection or dodge). It only applies to the specific thing it's attached to, increasing its bonus. +1 leather armor doesn't provide +2 armor and +1 enhancement, it provides +3 armor. I can't find the general quote but the specific quote on armor is: "Enhancement Bonuses: Enhancement bonuses apply to your armor to increase the armor bonus it provides."What page can I find this on? (And thank you for giving quotes, as that helps more than just opinions, as that's all I had before :P)
I'm not sure if it does outright say that. But if you look at any monster with magic armor, it is clear.
For example, the solar angel has +5 full plate. If you look at the AC breakdown, it does not say "+9 armor, +5 armor enhancement bonus". It instead says "+14 armor".
AC 44, touch 11, flat-footed 42 (+14 armor, +1 Dex, +1 dodge, +19 natural, –1 size; +4 deflection vs. evil)
Treasure double (+5 full plate, +5 dancing greatsword, +5 composite longbow [+9 Str bonus])
Just threw an edit down on my message, and that is a true point for that, but it's not exactly rules tight. But it is a starting point!
Edit: Found this on d20pfsrd
An enhancement bonus represents an increase in the sturdiness and/or effectiveness of armor or natural armor, or the effectiveness of a weapon, or a general bonus to an ability score. Multiple enhancement bonuses on the same object (in the case of armor and weapons), creature (in the case of natural armor), or ability score do not stack. Only the highest enhancement bonus applies. Since enhancement bonuses to armor or natural armor effectively increase the armor or natural armor’s bonus to AC, they don’t apply against touch attacks.
d20PFSRD is not a good place to look for rule information. They have been known to add their own interpretation to stuff. In this case, that table the quote comes from does not exist in the actual rules.
However, from the Combat section of the official PRD:
Enhancement Bonuses: Enhancement bonuses apply to your armor to increase the armor bonus it provides.
Edit: Found this on d20pfsrd
An enhancement bonus represents an increase in the sturdiness and/or effectiveness of armor or natural armor, or the effectiveness of a weapon, or a general bonus to an ability score. Multiple enhancement bonuses on the same object (in the case of armor and weapons), creature (in the case of natural armor), or ability score do not stack. Only the highest enhancement bonus applies. Since enhancement bonuses to armor or natural armor effectively increase the armor or natural armor’s bonus to AC, they don’t apply against touch attacks.d20PFSRD is not a good place to look for rule information. They have been known to add their own interpretation to stuff.
However, from the Combat section of the official PRD:
Enhancement Bonuses: Enhancement bonuses apply to your armor to increase the armor bonus it provides.
Yeah, that looks pretty cut and dry to me! Thanks! (And yeah, I know d20pfsrd isn't a good site for rules for that reason, it's just sometimes far easier to navigate.)