Is your mortgage $1200? If so, and if you want to take half of your mortgage from each paycheck, you'd budget $600 from your first check, which gives you a category balance of $600. With the next paycheck, add $600 to how much you budgeted, so that the total category balance equals $1200.
"It’s still all about the method. Fancy Cloud Sync algorithm aside...the software is there to help you become more aware (Rule One), anticipatory (Rule Two), flexible (Rule Three), and secure."--Jesse's blog, A Method to Your Madness