Here's the full text. The uppercase "UP TO" was added in the Jan Fasttrack.

17.1.4.D.7.a.1 Cars originally equipped with twelve (12) inch wheels may fit thirteen (13) inch wheels. Cars originally equipped with metric 365 wheels may fit fourteen (14) inch wheels, and cars originally equipped with metric 390 wheels may fit fifteen (15) inch wheels. The above-mentioned cars as well as those cars originally equipped with thirteen (13) inch or fourteen (14) inch wheels may fit UP TO fifteen (15) inch wheels. All other cars shall retain the wheel diameter fitted as original equipment for their make, model, and type. Knockoff/quickchange type wheels are prohibited. Wheels must be made of metal.