[GNC] Another "multi-account" logical issue - any advice on how to register this?

[Boniforti Flavio]

Hi all.
I'm again stuck with a specific type of transaction and would like to have
it validated (or corrected). Suggestions on how you would do it are welcome
as well - I might not be using the most intuitive way of registering it.

So...

I bought an item for 300. Paid for it from my checking account.
I paid for shipping separately 10. Paid for this as well from my checking
account.
Sold the item for 320, which was wire-transferred into my checking account.
I have earned 10 from the transaction.

I have created an account for that item:
Assets:Material:Item #1
Also, I've added a shipping sub-account to it:
Assets:Material:Item #1:Shipping

Then I entered the split transaction as follows:

PURCHASE =
Increase "Assets:Material:Item #1" of 300.
Increase "Assets:Material:Item #1:Shipping" of 10.
Decrease "Checking account" by 300.
Decrease "Checking account" by 10.
As I also have an account for "Postage expenses", how would I have to
register the 10 bucks I spent for shipping, so that it also accounts
towards the postage expenses in general?

SALE =
Increase "Checking account" by 320.
Decrease "Assets:Material:Item #1:Shipping" by 10.
Decrease "Assets:Material:Item #1" by 300.
Increase "Sales Surplus" by 10.

Thanks (again) for your help!
F.

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