You never signed anything when the installer came to your house and activated the 622? That's usually a mandatory action.
Even if they didn't say anything about a commitment, that doesn't mean a thing. If you did sign a document for your installer, certifying your installation, then it is likely that the lease commitment was attached to it.
I know the 942 lease upgrades that were arranged through the Dish CEO office had the standard 12 month commitment.
If you are wondering about it, you could call a CSR and ask them if your account has any commitment attached to it. You could ask that if you terminated your 622, would there be any financial obligation on your part.