actually it depends alot on what brand of flooring it is... I personally have a 270 on mine and it hasn't has so much as a sliver of a gap and no puckering at the seams... a good quality flooring holds firm to eachother and won't expand and contract very much... it's the cheapo flooring that will have a problem....
Also something to consider is if your flooring is applied directly to a concrete floor or if there is some sort of insulator in there... even just plywood...This makes a huge difference in the amount of movement of the floor as the concrete will pass temperature variations quickly to your floor and can create a situation that makes the floor more likely to expand and contract...
Just some thoughts for ya from a jack of all trades ... master of all of them