Name of this method
This is the internal name used for the shipping method, and should be a single word, like "air1". The order you enter the shipping methods is the order in which they will be presented to the customer. We recommend starting with the most common or least expensive method first. Here are some commonly used names for various shipping methods: standard ground shipping, standard flat rate shipping, three day shipping, second day shipping, next day air shipping, International shipping, US Mail shipping, etc.

Label for this method
The name you specify here will appear in the list of available shipping methods shown to shoppers when they place orders. Take care to make them easy-to-understand. The name you enter should reflect the shipping algorithm you choose.

Calculate based on this algorithm

Minimum shipping charge
The amount you enter into this field will be the minimum allowed quote for that particular shipping method. For example, if you want to charge no less than $4.50 for ground shipping, enter "4.5" or "4.50" into this field. Remember, you must set the minimum for each of your shipping methods, if you want each to have a minimum charge.

Additional shipping calculation
Here, you can enter any additional calculation you would like to apply to the shipping calculation. This is especially useful for the zones-based shipping calculations. Very few merchants pay the full rates for UPS shipping, and some merchants want to slightly mark up their shipping charges for handling. Other merchants may want to discount them slightly to promote goodwill. This feature would allow you to discount your UPS ground shipping quote by 25% to match your discount, then add $2.50 to cover a packaging and handling charge. Tip: if you're currently not receiving a discount on your shipping rates, call UPS and ask for one.

Although the shipping calculation engine that comes with Interchange is flexible and versatile, we realized that it still might not meet the needs of all users. We decided to include a feature that would allow Interchange administrators to modify the shipping charges that were calculated in a simple way. The "additional shipping calculation" field can be used to enter a mathematical expression that will be applied to a calculated shipping charge. Here's how it works.

Every shipping method needs to have a shipping algorithm associated with it. The algorithm could be "shipping by total cost", "shipping by quantity", or even a UPS weight based calculation. The administrator will typically have the option to set up several parameters that the algorithm uses. The administrator then names the shipping method whatever he/she wants. All available shipping methods are presented to the customer when he/she shops. Based on the method chosen, a shipping charge is calculated.

The shipping algorithm calculates a "base shipping charge." That charge may be modified by using the "additional shipping calculation" field.

Let's look at an example. Suppose that I want to implement a UPS based shipping system. I create three shipping methods, and call them "Regular", "Second day air" and "Next day air." Each method uses a corresponding UPS algorithm that calculates the shipping charge based on the weight of the customer's order, the UPS rate and zone tables. Easy enough -- but suppose that I have a special deal with UPS that gives me a 10% discount off the standard rate tables, because I ship a large volume of goods. Obviously, I don't want have to manually edit the rate tables. Instead I can use the "additional shipping calculation" field to automatically apply a 10% discount to whatever the UPS rate would have calculated.

In the "additional shipping calculation" field, I would enter the following:

x = x - (x * .1)

The character "x" represents the shipping charge as calculated by the UPS algorithm. Interchange will automatically apply the above formula to the shipping charge, and charge the customer the new total.

Here's how it would work for a real customer. Customer A enters the site and orders 50 lbs. of goods to be shipped to Alaska by next day air. The UPS algorithm determines that the cost would be $400. Interchange then substitutes 400 for "x" in your formula:

new charge = 400 - (400 * .1)

The resultant charge is 400 - 40 dollars, or $360.

Of course, we could have also written the formula this way:

x = x * .9

which would have had exactly the same effect. If you're a Perl guru, you'll be happy to know that you could also have written

x *= .9

It is important to note that you must specify some sort of equality on the left hand side of the equation.

You can enter any valid mathematical expression and you can reuse the "x" variable as many times as you need to. Interchange validates the expression you enter, so if you make a mistake it will inform you, and the additional shipping calculation field will not be updated.

All invalid characters are stripped out before Interchange processes your equation. This means that if you type in something like:

x = x * y + 300

the "y" will be removed, and Interchange will see

x = x * + 300

which is an invalid equation.

Valid expressions include (but are not limited to) such things as:

x = x + 5
x = x + 5 + (x * .1)
x = x - .75
x += 2
x -= (x * .25)

etc.

As you can see, there's more than one way to enter any given expression.

Valid characters are x+-/*.()0123456789

If for any reason a shipping algorithm fails, the additional shipping calculation will not be executed.