Could be a number of reasons, but Scott Maclachlan has a young family and also represents other artists.
Perhaps there is a limited amount of time for one artist and considering the amount of money he'd be making from Ella (assuming a standard percentage), she might be looking for a different arrangement once the next era is underway.
Plus there appears to be some arrangement with the Windish Agency for her US tours at least.
http://www.windishagency.com/articles/798
I'm wondering what this means for Jimmy Mac and Ben Barter. I believe that they were introduced to Ella via Scott.
