To check the index, click on the blue ‘Details’ text (hidden behind the drop down-menu in this screen capture) and choose ‘Allocations’ from the drop down menu.
In the window that opens, click on the blue ‘Summary’ button.
The list of indexes being charged (i.e. allocated) will open in a new window.
TIP: See the ‘Changing the Index (i.e. who is paying for the expense/s)’ for steps required to change an index.