Five major US agencies have (temporarily) eliminated booking fees on air tickets. Now, Orbitz is escalating the fight against its competitors by changing its display of rates and reducing the booking fee on hotel rooms.

Orbitz will show the total of base rate, taxes, and fees on the search results page. (No word on mandatory charges like resort fees that hotels hide from searches.)

How much of a change is this? On the surface, this is a positive step toward greater price transparency. But is it really a big shift? Since hotel searches are geographically limited, taxes rise proportionally with base rates. Lower rates would, by definition, mean lower total prices. (This is unlike airfares, where base fares on two airlines may be the same, but the total prices may vary based on the number of stopovers or the airports involved.)

In terms of fees, the simultaneous reduction and integration of fees in results muddies things. Orbitz says they’re reducing hotel booking fees charged by the site, with a sunset clause that expires the reduction after July 15, 2009.

But who would notice? Since the fees aren’t itemized, it’s hard to see what the actual fee to Orbitz is. Customers may not care about whom they’re paying their fees to, but it’s not really transparent.

At first, I thought this would put pressure on Priceline, which claims to be “working hard to keep priceline’s hotel booking fees lower than Expedia, Travelocity, Orbitz, and even Hotels.com.” But if Orbitz fees aren’t broken out, then the real pressure is to show total cost up front.

As far as transparency is concerned, this is still a good move. Let’s hope these changes gain sway with others, and that they last beyond July 15.