What is the difference between `Home page / Archieves` and the page set as homepage?

“Home page / Archives” stat doesn’t necessarily represent the number of views of a single page, although it might if your front page is a static page. The meaning of, and reason for, the designation was briefly addressed by staff member macmanx, shortly after WordPress evidently changed this stat from “Home page” to “Home page / Archives,” in an April 2012 topic titled “My stats.”. macmanx said,

This is an intentional change. Date and category archive listings are actually counted the same as the Home Page when the home page is set to display posts.

Therefore, what you originally saw for your Home Page total was a collection of Home Page views and Archive views, which is why we changed the title to the much more accurate “Home Page / Archives”.