Your math looks solid - total savings of $4,800 for leaving the lease early. Strictly speaking, when you pay a fee for early termination, you're not "breaking the lease," you're complying with the terms of the agreement.
I'd be sure to deal with it cleanly with the landlord. Talk first, and see if you can get out of the fee, because sometimes that's possible if they can re-rent the place. Once you've talked, give notice as soon as you can, in writing. Keep copies. Get the landlord to sign something indicating that he's received notice, and describing your understanding of the fee agreement - basically, put something in there like "In accordance with the terms of our rental agreement, and our conversation on Day/Month, I understand that we will owe a fee of $XXX for early termination of the lease." And maybe say when you intend to pay it - when you vacate, when the landlord returns your security deposit?
Make copies of the check, note when it clears the bank, keep this stuff on file - but this really should not be a problem.