Existential Perfection

What is the difference between Perfection and Existential Perfection ? Can anyone explain to me ?

This is something I've really not been sure about for quite some time. It feels like all of the attributes associated with Existential Perfection ("complete, absolute, and infinite in all senses and aspects with no limitation that could possibly apply to them") would entail Perfection, and vice versa. Also, Existential Perfection is stated to have all those qualities "while the user exists", implying that a being who is "complete, absolute, and infinite in all senses and aspects" could exist at one point but not at another (as in, if they have those qualities, then they should be an Eternal Existence as well).

Then there's the way Existential Perfection is defined as an ability - "The power to be perfect in terms of existence." What does that even mean? And again, how does being perfect in terms of existence differ from being just 'perfect'?

So yeah, I really don't get Existential Perfection as an ability, especially in relation to Perfection.

What do you think?