If you outright purchase the property and pay for it with cash, then I seriously doubt financing the property later (even one day later) would be of any benefit. Your loan must be for the acquisition of the program, and a refi must be for refinancing the original acquisition loan on the property. Since you will not have any acquisition debt, I don't think any of the mortgage interest would be deductible at all.
Acquisition debt is a financial obligation taken on during the construction, improvement, or purchase of a primary or secondary residence. Thus, a home mortgage loan is an example of acquisition debt.
So if you're paying cash for the property, you own it free and clear. Then, if you take out a loan against that property the debt incurred is not acquisition debt, since you already "acquired" the property with cash.
@M-MTax I thought pub 936 addressed this. But I can't seem to locate it in that publication. I do find references to the debt being "secured" though. But I know I've read somewhere about acqusition debt - possibly in another pub. Can you clarify things here please?
