Smart to pay down the mortgage sooner with low interest rate?!

[Kegan Brenner]

Hello all, I am new to the group and wanted to start by asking a question on our business office building. My wife and I own a dental practice and purchased our building. Purchase price was $2M and we financed $1.7M @ 4.32%. Our mortgage payment is $12,849.05 per month. Now I know with that we got a great interest rate and at first I planned to not pay it off early as our tax break is helpful. However, now that we are exploring real estate more I was considering paying off the mortgage earlier to have more cash each month to invest elsewhere. My questions are:

a) Is it worth paying that 15 year note off earlier with that interest rate?

b) If so, does anyone recommend the method of making 2 half payments per month? Is this a good strategy that actually reduces the life of the loan? When using this method, how do I go about this with my bank?

Thank you all in advance!