Simple, as people stated previously, statistics update from time to time, and some of them update quicker while others slower. Same thing for different sections on the whole website. Your own hidden creator profile will have the most recent stats, while the public ones might take a bit more time to update.
Opening something is considered a view, no matter who does it and if they have an account. Total views are ALL VIEWS of the Synopsis page and all chapters summed up. Total views (chapters) is only those from chapters. Average views are TOTAL VIEWS (CHAPTERS) divided by the TOTAL NUMBER OF RELEASED CHAPTERS.
Different numbers of views around chapters are normal. People sometimes click on them not in order, to check on something, reread, or by accident. And that naturally may give more views in the further chapters than the earlier ones.