TrakCare - Order Item - What is the difference between Apply and Update?

I may be mistaken, but I believe that "Apply" will persist the change and keep you on that screen, while "Update" will persist the change and close the screen.  Does it seem to work that way? (I don't have a TC instance here to test with a.t.m.)

Ben is correct. 

Apply saves the current state and Update saves and continues the workflow/returns you to the previous screen.