The most common reason that your sales from Amazon do not match the KDP dashboard is that you're looking at a different data source than we are. Most people look at the sales chart on the Sales Dashboard page of KDP. It gives a very concise view of your sales over a period of time. However, the data on it is summarized and not detailed. It does not show which books generated those sales, or in which countries those sales took place.
In order for BookTrakr to provide that sort of analysis, we need a different data source that has the necessary level of detail. The source we use is the Sales Report, which can be downloaded from the same page that displays the chart. Simply click on the "Generate Report" button at the bottom of the page, and KDP will download a detailed sales report. That is what we use as the basis for reporting your KDP sales.
The sales report often reports differently than the sales chart because the chart is based on "orders", while the report is based on "sales". Usually there is no difference between the two, but occasionally it take a while for the order to become a sale (if the card is declined or the gift card is not redeemed immediately); when that happens the two data sources offer differing numbers. We work based on the "sales" number, which is also the basis on which you are paid.