Buying For Cash / Refinancing Question

Hope someone can help me with this; I'm new.

I have access to enough cash to buy a good rental property. My preliminary plan is to offer all cash, and hope that the seller will take about 5k less than his asking price (I don't think this will be a problem).

I then plan to refinance for the value of the home and repeat the process. I have enough cushion, so that isn't a problem. My question is this:

I know that when I buy my 2nd rental, they will only allow 75% of the rental income to go to the mortgage when I refinance (I think I'm right--please correct me if I'm wrong..) If I do a 3rd this way, will the percentage of the rental income allocated to the mortgage be based on the rental income from the first property or the second? I guess what I'm asking is, is it a "stair-step" kind of thing, or is it all based on the rent from the first property?

Like I said, I'm new, and this may not have made much sense. I'd appreciate any feedback though. Thanks.