Conceptually, there is one Standard Pricebook and there are many custom Pricebooks. This allows you to do the following:
- For SKU xyz, the standard pricebook price could be $10.00
- For the same SKU xyz, on the pricebook called Commercial, the price is $10.00
- For the same SKU xyz, on the pricebook called US Government, the price is only $8.00
When you create a pricebookEntry for the junction between Product2 and Standard Pricebook, set useStandardPricebook to false. All pricebookEntries on standard Pricebook have useStandardPrice = false
When you create a pricebookEntry for the junction between Product2 xyz and Pricebook US Government, set useStandardPricebook to false and set unitPrice to 8.00.
On custom pricebook called 'Commercial' where SKU xyz is $10.00, then when you create a pricebookEntry for the junction between Product2 xyz and Pricebook Commercial, set useStandardPricebook to true and set unitPrice to 10.00.
In effect, your updates to PricebookEntry are mimicing the SFDC Force.com user interface where you define standard pricebook prices for a Product and then, if you use custom pricebooks, you can choose to use the standard price or override the standard price, just for that pricebook.
Don't forget that all pricebook entries must be inserted against the Standard pricebook before you can insert pricebookEntries on custom pricebooks.
Saturn Price Book is a custom Price Book. Standard Price Book is as the name suggests, is the standard Price Book containing all Products and their standard price.
An opportunity can only have one Price Book selected at a time. It is possible to have the Price Book defaulted by some other configuration/customisation in your org so the user does not need to make a conscious decision to select it each time.
You can change Price Books, but doing this will remove all Opportunity Products as you cannot mix Pricebooks on a single Opportunity.
Does this help?
Best Answer
When setting up percent of total product, you do need to create a price book entry with a price. It doesn't really matter what you put in there unless you want to have a minimum or maximum price for the percent of total product (you'd use the Percent of Total Constraint Field in that case).
For your second question: you can have percent of total on yearly products. If you are running into a specific problem, I'd recommend a new question.