Residential vs. non-residential mortgage

[Simcha Davidman]

I recently got pre-qualified (waiting for the pre-approval letter any day now) for a mortgage on a residential property.  The broker asked whether this would be for my residence or investment, and I told him it's an investment.  I have two questions.

(1) How does that effect the underwriting and ultimate mortgage I may obtain?

(2) How legitimate is it to say that I "might" live there?  In other words, at what point does it become shady to say that I might live there?  I am under the impression that "some people" do this in order to obtain better financing.  Right now, I only own one property and I live in it.  While I do not plan on moving to a new property, I theoretically could move into the new one and then rent out my current residence, right?  I doesn't sound right to me, but I am hoping for some interesting feedback.

Maybe my gut is right and I should avoid this because it is seriously problematic.  Maybe my impression that lots of people do say they "might" live there when having no intention on it is not accurate.  Or, perhaps, this barely figures into the underwriting/decision-making at all?

Any and all feedback is appreciated.  Thanks!