gracie,,larger format tiles have a tendency to bow or cup in the middle. this is from the firing phase with ceramic and porcelain. this is what you don't want
laying them in the other pattern minimizes the effect. some tiles are more bowed than others. usually the tile manufacturer will list the layout requirement for their tiles. look on the specifications for the tile you ordered. what do they recommend? sometimes they recommend 25% offset,,,,and you will have to go w/a larger grout line in some instances.
33% Offset Pattern
Note that the offset specified in the ANSI standard is not a 50% offset. The reason is that this pattern amplifies actual tile warpage and likely results in unacceptable lippage in the finished installation.
In other words, the tile should be set in a 33% offset pattern unless the manufacturer specifies an even smaller offset (e.g., 25% offset).
In addition, the grout joint size should be widened to help lessen the effects of lippage caused by actual warpage in the installation. ANSI A108.02 4.3.7 discusses criteria for lippage which includes allowances for workmanship.
Check the tile carton; if it isn't stamped with information indicating that it meets A137.1, contact the manufacturer or distributor. They will be able to tell you whether the tile meets ANSI A137.1.
this is the allowable warpage standards
Q