2nd place has won twice more levels than 1rst place ? Why is she 2nd ?

My wife "DG" is currently in second place of the all stars contest and has won 2,518 levels and has played non stop for the past 20 + hours. The person who is in first place "Lisa" has only won 1,482 levels , so 1036 levels less but has more points. Her profile also says "played yesterday". Can someone please explain how the points are being counted ? Are easier levels providing more points than harder levels ? I know they are supposed to collect purple stars to get points but how does someone with 1000 more levels completed have less points? Do lower levels provide more purple stars? Can someone please explain... see the screenshots below.