Stacking versus Double Stacking via multiple means

[FrodoOf9Fingers]

So, I've hit this a couple times in the forums, and I want to try and understand this concept a little better. When does double stacking apply? Here's the situation it came up in.

Situation 1
Wizard 20 using a familiar has the feat "Eldritch Heritage: arcane".

Versus

Situation 2
Fighter 10 Wizard 10 using a bonded familiar, with the feat "Eldritch Heritage: arcane"

Relevant information:

Spoiler:

Benefit: Select one sorcerer bloodline. You must have Skill focus in the class skill that bloodline grants to a sorcerer at 1st level (for example, Heal for the celestial bloodline). This bloodline cannot be a bloodline you already have. You gain the first-level bloodline power for the selected bloodline. For purposes of using that power, treat your sorcerer level as equal to your character level – 2, even if you have levels in sorcerer. You do not gain any of the other bloodline abilities.

Spoiler:

Arcane Bond (Su): At 1st level, you gain an arcane bond, as a wizard equal to your sorcerer level. Your sorcerer levels stack with any wizard levels you possess when determining the powers of your familiar or bonded object. This ability does not allow you to have both a familiar and a bonded item. Once per day, your bond item allows you to cast any one of our spells known (unlike a wizard's bonded item, which allows him to cast any one spell in his spellbook).

So, correct me if I'm wrong (and give me some slack if somethings wrong with the RAW, it's more of an example trying to demonstrate stacking vs double counting) here's what the math looks like in my mind:

Situation 1
EWLs (effective wizard level) = wizard levels + (total character level -2 from eldritch heritage) = 38

Situation 2
EWLs = wizard levels + (total character level -2 from eldritch heritage)
= 28

Some say that I am "double counting" my levels, and thus should not be allowed to do this. I am counting my total character levels, and then my wizard levels which have already been counted. Even though it would stack, it doesn't because of double counting.

According to double counting, the math should really appear as:

Situation 1
EWLs = wizard levels + (total character levels - wizard levels) = 20

Situation 2
EWLs = wizard levels + (total character levels - wizard levels) = 18

Where is the rules regarding double counting? What are those rules exactly? In what circumstances do they apply? In what circumstances do they not apply?

[Mojorat]

Well the problem is that when feats are written they csnt take in every possible combination.

If you had wizard 10 sorcerer arcane heritage 10 the rules are easy.

Really though stric raw shoukd be filtered through common sense. The fact that there are no rules in the gsme for familiar lvl 38 or 28 tells us that math is probably wrong.

[FrodoOf9Fingers]

Mojorat wrote:

The fact that there are no rules in the gsme for familiar lvl 38 or 28 tells us that math is probably wrong.

Yet characters can progress from levels 20-30, even though there is no graphs for that level.

Wizard 10/sorcerer arcane 10 is easy. Thats 20. It specifically states it stacks. But what isn't is Wizard 20 with the eldritch heritage: arcane feat.

[Samasboy1]

Common sense doesn't mean the same thing to different people, which is why so many discussions on the boards center on RAW.

One GM will have no problem with a character having a level 38 familiar at 20th level. Others will see it as a problem.

[blahpers]

What, exactly, do you get for having a level 38 familiar? More natural armor?

[BigDTBone]

blahpers wrote:

What, exactly, do you get for having a level 38 familiar? More natural armor?

That and it would have a 29 INT. I would let it double stack. It's just not a huge benefit even after spending 2 feats and having less than optimal stats to make it happen.

[FrodoOf9Fingers]

Letting it double stack simply because it isn't powerful isn't the point I want to get at. I want to know:

Does (Character level) + (class level) = double counting? They use two different numbers, Character levels and class levels are not the same, though one is derived from the other.

That and Where does it say that you cannot double count? I've peeked around, and cannot find it. Is there a place in the rules saying that? Or is it simply GM's making the rule to prevent something else?