Please refer to the Elder Scrolls mythos in which this is the case.
This is the case for most mythological sons that are not naturally procreated. In ES canon this is a precedent. If there's no opposite partner, no devoured deity, then Al comes from Ak, hence they are the same, deferring to logical mythological example.
Ak did not create Al in his presence, Al came from his presence. More than just a seed, an embodiment of Ak. Take into account the whole cycle and How Ak came to be, along with his role in Nirn, its not hard to see how they are the same.
According to the friendly Dragons in-game, they are all sons of Akatosh, are you saying every Dragon I have killed is Akatosh!?!?!? *gasp* Plus, where in Elder scrolls lore does it say that if you are the son of a god, you are that god. If so Tibre Septims kids would be gods, heck this isnt even the case in real life, Hercules was Zeus' son but wasnt Zeus himself, Thor was the son of Odin but they were not one and the same, your logic is flawed.
No, my logic is not flawed. Al was not mothered. Al came from Aks being. Its more closely related to christian mythos than Greek or Roman, even though it is a polytheistic religion.