@Jason Fox - first things first, 1%/2% "rules" should never be considered a lock in any way. You can lose money on a 3% house, and make money on a 0.5% house; a savvy investor has to dig a heck of a lot deeper than comparing rents to purchase price.
I think the thing that stands out to me is that you have zero reserve expense built into your numbers, it looks like you consider anything that isn't PITI to be straight profit.
Unless you intend to sell the properties within the next 5yrs. or so, at some point you WILL have cap-ex, maintenance expenses, etc. For example: say you have a new composition roof. That's only going to last you 15-20yrs. (we'll say 20) and will cost about $15,000 to replace. Thus you should have a Roof, Cap-Ex expense of $62.50 that you pull out every month for when you do eventually need to replace it.
Take these items into account and take another look at your "profit" to see if the cash-flow still meets your requirements, what's your ROI on the down payment investments?.