That should suffice, the maximum rating is normally based on the leds showing 'all-channels' at full brightness, basically bright white. I have always used a 10% margin minimum, but have come to the conclusion that the powerratings provided with strip are generally exaggerated, and the manufacturer has also put such a margin.
Those are fine for indoor use. Keep in mind that you can power 'through' the strip for a maximum of 5M. You are saying you will split the strip in sections, but if you do not, you will have to feed power into the strip every 5M or so. Also make sure you use decent power cable for the power line and the thin stuff for the data line (thicker is not better for the data line)