JACKSON, Wyo. (AP) — The cost of staying in some of Yellowstone National Park's most historic lodges increased by up to a third this summer under a new, pilot pricing system that allows the lodging concessionaire more leeway in setting room rates. But the change has drawn criticism that some people might be priced out of a stay in the nation's first national park. In recent years, Yellowstone hotel rates have been set using a comparability analysis that aligns costs with those at similar hotels in gateway communities like Jackson, Cody and Gardiner, Montana. But this summer park managers adopted a newly authorized National Park Service pricing system that applies to park concessionaire Xanterra's room rates. Using the new approach, Yellowstone is divvying its hotels into "core" and "non-core" facilities under what's being called a pilot project.