Price Factor

[farris12]

I'm selling paint, selling it per litre.

I sell 2,5, 5 and 10 litre cans.

My prices are per litre, ie:
2.5litre: $5 per litre
5 litre: $4.5 per litre
etc.

What I want on my product page:
A dropdown with the option to choose a can (2.5/5/10 litre)
So I selected Price by Attribute and I maked 3 attributes:
2.5
5
10

The 2.5 attribute has the following options:
Price: $5 (because it's $5 per litre)
Weight: 2.5
Price Factor: 2.5 (because it's 2.5 litre)

But, Zen calculates it wrong... I don't get $12.50 but something else (Tax included)

What am I doing wrong?

Here's a link:
LINK
additional info is on the product page

[Ajeh]

The Price Factor is used to compute the Product Price * Price Factor ... then if there are additional charges on the Attribute for an Attribute Price that is added in ...

If you also mark the Product as Priced by Attribute, you will get some really weird results ...

If you edit the Product and set the Product Price to 5.00 and mark it as Priced by Attribute NO ...

Then, go to the Attribute for the 2.5, then you will get:
Product Price + Product Price * Price Factor
5.00 + 5.00 * 2.5 = 17.50

If you include an Price Offset of 1.00 you will get:
5.00 + 5.00 * (2.5 - 1) = 12.50

[farris12]

Why do I have to make the price 5.0?

It's only $5 per litre when it's 2.5 litre...
It's $4.5 per litre when the costumer buys 5 litre, etc etc

How do I have to make that in ZC?

[Ajeh]

There are a number of ways to price this ...

Using the Price Factor, you need to set a Product Price ... otherwise, you cannot use the Price Factor ...

You could put the full price on the Attribute and then when they buy at the 2.5 liter they get the 2.5 liter price ...

It all depends on how you want the initial price to look ...

[farris12]

ok .

I think I can't use a fixed price, because of the fact that the pice depends on the # of liters...
So I think the best way is to doit with Attributes, isn't it?
But do I have to do something with the + or - in the attributes?

When there will be a new version of ZC (ever), they have to make this clearier...

[Ajeh]

On attributes, the + or blank is add to the Product Price (if any) and the - is subtract from it ...