Does having two class engravings cancel each other out?

I was experimenting with having two Class Engravings on and it only just dawned on me that you can do this.

On testing, having both does not consume all orbs but only consumes one and adds 1 more orb - totalling 4 orbs.

So now I have too many orbs hahaha. So build rn is Spec, Crit, Swift.