Dr house is correct when he says that painting a deck is a horrible idea, whether you strip and clean it, or not. paint does not have the same durability as a stain. Whatever you do, DO NOT PRESSURE WASH YOUR DECK! EVER! it causes the fibers in the wood to split and fray off. Ruining the wood on your deck. Decks get alot of wear and tear. Behr paint is great paint if the user follows the instructions and doesnt try to paint over a stained deck or a previously painted deck. Once you apply a product to any type of wood it seals the wood off from having another product put over top. Do not apply paint in the middle of the day, same with stain, itd too hot for the product to handle it, Paint and stains have water in them, if you do it in the middle of the day the water evaporates faster than the product has time to dry. While it looks good at the time, it will peel in a couple months. Do it in the morning! when its cooler out!!!
Also! colour matching will never be the same as the chip, because most paint companies do not put their chip in a flat finish! They use shine on their chips so you cant colour match it. That way you have to buy their paint. If you bring in a sample from your own wall it has to be big enough to colour match, otherwise you need to pick a colour off the colour wall to see if you can get it close to the colour that you have.
I hope this has helped somewhat. Good luck!