Creating Layouts based on similar existing ones

I’ve create a layout for desktop with a landscape aspect ratio and a layout for iPhone with a portrait aspect ratio… However, when I try to create a layout for iPad in portrait or landscape I seem to only be given a new layout based on the last layout I created. It would be useful if I were able to select an existing layout that has the appropriate aspect ratio to make tweaking a breeze! Am I doing something wrong or could this be a improvement that others could benefit from also?