Concur with all of the above... PL bidding is not for the faint of heart or the uninitiated, and luckily there are two websites that can help you. I prefer betterbidding because of their friendlier tone to newbies, but you may find information of value at either site.
As Romelle pointed out, the map of the zone is the deciding factor. Sometimes the zones are given ambiguous or downright deceptive names, but if the hotel is in the shaded area they showed you, you got what you paid for.
When it comes to bidding on PL, flexibility is key.