In my above examples, I do wonder about one thing though. For example:
fire/fire/fire results in one thing because you get fire/fire at second and fire/fire at third
fire/fire/air in another because you get fire/fire at second and fire/air at third
fire/air/fire in another because you get fire/air at second and fire/fire at third
In the last two examples, I wonder if the second level fire/fire has a different bonus than the third level fire/fire. Just like each altar imparts differnent things, what level you take the combo may do different things.
In other words, say for example you have earth/fire at the second tier, you get magma I.
But, at the third tier, suppose you don't have magma I, if you have the earth/fire combination for the third tier, do you get magma II, or do you get magma I? In other words, is the strength of the combo dependant upon whether it was done at tier 2 or tier 3, or is the strength of the combo dependant upon if you have the earlier form or not.