Yes you can.

But I also look at it this way, do I have enough paint for a second coat? Because I'd rather just paint the room again rather than worry about how to dispose of leftover paint LOL.

And to be honest you start noticing more spots over time.

And in the future, just FYI unless there is a very specific reason to use Killz, like for example you bought a house where people previously smoked, it's usually better to not prime and just do two regular coats. Because the primer can just cause a situation where you need to paint more.