So yeah - it's ready to vape.
If you add flavor, it will be a little under 6 mg strength, but so what?
You could add 3 mls of a flavor, and then fill the bottle to 30 mls with base.
You'd have 30 mls, that's got 10% flavoring, and that's 5.4 mg/ml strength.
To add flavoring and land at 6, you have to start higher.
That's why a lot of us start with un-vapeable 100 mg base, add flavor, and PG and VG with no-nic to bring it down to where we want it...