Discrepancies between Google Play sale order history and transaction payment list

Curious is anyone else has discrepancies in their Google Wallet order history and payments transactions for paid app sales? I have one paid app for sale at £2.49. On 22nd Oct, for example, I show 6 chargeable sales in the order history, with all of the sales in the same currency, GBP (my app is highly localized to the UK). With Google taking 30%, this should yield £4.50 to Google and £10.44 to me. However the transaction history for this day shows £2.23 to Google and £12.67 to me. The totals don’t match up either. I’ve seen this same on most other days too. Oct 19th had 7 sales and so I expected £5.23 to Google and £12.20 to me, but transaction history shows £3.36 to Google and £15.54 to me. Now, I’m certainly not complaining to Google since in every instance I seem to come out ahead of my expectations, but can anyone enlighten me on why there is a difference?

It’s probably caused by VAT - Google doesn’t take 30% from it I think.