The A320 FCTM says that, as long as the trim is within the green band, the takeoff is safe. Rotation characteristics may vary though. But the latter can also be the case if the calculated CG from the loadsheet is slightly off because the real distribution of the load doesn't fully match the calculated one. It can happen on flights with a low number of passengers who get to sit wherever they please. Although that's more of an anecdotal evidence, based on experience and observations, they tend to distribute themselves as evenly throughout the cabin as no computer would distribute them.
