Edward, you performing a test with your friend or using your own app sales data is not definite proof of the problem, You really are not in a position to make out you know what is going on with Google Play.
You are just making assumptions bases on your own data.
Google Play has been working fine until a few days ago. Google "google play errors" and you will see the new headlines about this issue.
Sales have picked up a bit for me since yesterday but as I mentioned before I think the Google Play server errors are now less frequent but they could still be happening on a global scale.
People already do not really buy a lot on Google Play and this will be just another nail in the coffin of consumer confidence of the Android market in general...