Newbie's question on discount rate

[X Sun]

Hey guys,

New to real estate investment. I am trying to wrap my head around into discount rate.

I find this online calculator (https://www.mtgprofessor.com//calculators/Calculator11a.html) which will take tax, opportunity cost, etc., into account. 

Hypothetically, these are the quotations for loan amount = $228,750. By math, it seems that the higher discount rate and lower interest always save more money (pretty short breakeven time according to the calculator).

So does it make sense to max out discount rate so total closing not exceeding 2% of sale price as long as we have enough cash? Did I miss anything?

Discount Rate	0.75	1.625	2.225	2.75
30 Yr Interest Rate	4	3.25	3	2.875