A1 / AMS / Print question

GIF folks
Heres my observation / query
Created a 3D model magsafe stand prints within 1.45 hrs when a single color

I imported into studio this morning and thought the top edges would look nice with a different color (Printing on mini no AMS attached)
Simply used the color fill on the topmost edges.

The print time went from 1.45 hrs to 7hrs 42mins.??

What am I missing, the only added time should be the filament change / flush etc