I'm having 3 quotes on replacing our units. The old ones were a 5 ton and a 2 ton units. However, each company is quoting me differently. First one is 5 and 2.5 ton units, Second is 4 and 4 ton units, third is 5 and 3.5 units. They are suppose to have done the J Calc? using 75 F indoor temp when outside is 94 (we're in FL). They are all quoting the Trane XR15 (15seer) units. Not sure which one I should sign the contract with??? Our house is 2 stories, first floor about 2500 sqft, second is about 2200 sqft with lots of windows and high ceilings. Any suggestions?