Paycheck parking and chunking get taught as two separate moves, and they look different on the surface. But underneath, both of them are pushing on the same single number. Get that number in your head and the whole approach stops feeling like a magic trick and starts feeling like arithmetic.
The number is your average daily balance. A line of credit generally charges interest on what you owe each day, then adds up those daily slivers over the billing cycle. So the balance that matters isn't what you owe on the first of the month or the last. It's the average across every single day. That's the lever. Everything else is just ways to push it down.
Parking pushes it down by timing. Your paycheck lands on the line the day it arrives, so the balance drops immediately and stays lower until bills pull it back up. The money was going to sit somewhere between payday and the day you spend it. Parked against the line, those idle dollars knock down the daily balance for the whole time they wait. Same dollars, doing a second job on the way through.
Chunking pushes it down a different way, by moving a block of fixed-rate debt onto the line and then burying it fast with cash flow. The line balance spikes when you take the chunk, then your income drags the average back down over the following months. The faster your monthly surplus can bury it, the lower the average sits and the less that chunk ever costs you.
The same math cuts both ways. If your spending drifts up, your average daily balance drifts up with it, and your interest bill follows. The routing only helps if your spending stays where it was. And a variable line can reprice against you, so leave room for the rate to climb a point or two without breaking the plan.
The full month, mapped out step by step, is on the How It Works page. Not sure it fits your household yet? The wider money picture is at Oregon Cash Flow Pro.