When is a sale not a sale?

A word on self-publishing sales

My official sales figures are much less than my actual sales. Official book sales figures – that you see quoted in the bestsellers list – are managed by Nielsen Book Data. All sales that are logged through the ‘system’ ie the booksellers’ tills plus Amazon sales are totted up.
However when you self-publish you are both author and publisher. With my publisher hat firmly on my head, I get an order from a shop for say 20 books, so that for me is a sale of 20 books. They have not yet sold in the shop and do not register officially as a sale until they do.
Moreover some small bookshops are not linked in to Nielsen Book Scan statistics; so any sale through them does not officially register.
Also if I am out and about giving a talk, or attending an event of some kind and I sell a few books, it won’t be recorded as an official sale, but I certainly count those as sales. And sometimes I supply direct – for example to local authorities who use them in the education service.
You can only view sales figures of your own books if you subscribe to Nielsen Book Scan service, which did cause murmurs of protest from authors at a seminar I attended a few weeks ago. However, I guess most larger publishers can easily bear the cost of that and one cannot expect a service requiring both people, time and technology for free.
If you self-publish you get the profit – that is the difference between the selling price and the price of producing the book, less discount which varies from say, 25% - 60%. Of course, there are other overheads, like postage, couriers, travel, publicity and so on; so with your business head also firmly screwed in under that hat, you need to watch those costs carefully, or you would inevitably end up with a financial loss.
I have heard, anecdotally, that some self-publishers using digital print on demand, where the unit cost is relatively high, have ended up having to pay Amazon to sell their book! Can this be true?
© Miriam Wakerly