Good for you on saving money from not locking your interest rate. 

What are your triggers to gets rates locked into for the long term?  You might have a good plan and IF things get crazy nobody might want to lock anything in for you and then you could be stuck paying very high intrest on your short term money.

Perfect example is when farmers wanted to sell corn near the end of the runup in 2008 and the buyers just said we aren't buying today. 

Andy