Mana cost issues for auto-leveled Ascendancy skills

Skills like Elemental Expression for the Invoker ascendancy auto levels as the character levels up.

However, Elemental Expression in particular is also an auto-cast ability that costs mana.

As a result, as the character levels up, the mana expenditure increases way more than what the character's mana regeneration scaling can sustain with no way of reducing it by deleveling as you can with other skills or using is less through manual activation.

I don't know if this is the intended result, but it seems to be reach the point where it becomes unusable at higher levels coupled with other increased mana costs of higher level skills.

Absolutely true, elemental expression becomes unusable because of high manacost