When the Apple Maps integration is enabled, and a user clicks on the Maps button from My Accounts it displays the distance to the account. When the Maps button is clicked from the Account Detail screen, a different distance displays.
Distance to the Account is calculated from the user's current location if the Maps button is clicked from the My Accounts screen. When the maps button is clicked from the Account Detail screen, the distance is calculated with the selected Account as the starting point.
CRM Help Documentation: Displaying Account Maps