Inventory, BBP Q6.19

The textbook gives the following the question:

A firm has the following transactions with its product R.

1 Jan opening inventory: nil
1 Feb Buys 10 units at $100 per unit
11 Feb Buys 12 units at $250 per unit
1 Apr Sells 8 units at $400 per unit
1 Aug Buys 6 units at $200 per unit
1 Dec Sells 12 units at $400 per unit

The firm uses AVCO to value its inventory. What is the inventory value at the end of the year?

The answers say it is $2,057.12.

But if I were to do the question the way you have described in the lectures, as well as the BBP textbook, shouldn’t the answer be $2,007.26? I thought that we needed to calculate a new weighted average each time we receive inventory. But the BBP answer seems to be using an accumulated average of all receipts.