Avoiding $0 charges for add-on rates

If you use auto-rates and a lot of your reservations end up with a charge of $0 for add-ons like Extra people or Extra pets when they have no extra people or pets, it's likely that the rate definition isn't quite correct.  This is a common mistake in the understanding of the "Applies if reservation field" setting of a rate definition.

For each of your add-on rates where you have:

 Applies if resv field _________ is >= ___  Per each more than ___

The first number should generally be 1 greater than the second, for instance:

 Applies if resv field _# Pets_ is >= _1_  Per each more than _0_

This is because >= means "greater than OR equal to", so you only want it to use the rate if it's greater than or equal to 1 pet.  For instance if you had 0 for the first number, it would try to add the rate even when there are no pets.  While the total is $0 and doesn't affect the charges, you don't really want it to show the extra pets charge of $0 on the receipt (not to mention being needless extra junk in the database).

Likewise if you charge for any adults more than 2, the rate should look like:

 Applies if resv field _# Adults_ is >= _3_  Per each more than _2_