One solution is to create separate measures for FY2014 and FY2015 then you can create the calculation for % Difference which will remain dynamic.
Duplicate for FY2015 and then create your % Difference calculation. Add all three to Text and you'll have dynamic data. You could go one step further to create a parameter to select year and a Lookup calculation for the % difference to drive the years pulling into the table.
I hope this helps.
Thanks and best,
Hide Column Example.twbx 1.2 MB
Thank you for such a quick response, much appreciated! I could try this option. I'm just thinking that it could get tricky because I am trying to allow the users to pick different measures, but theoretically I suppose it should work just the same. We will see.
Glad to help, it should work the same but without seeing your data there might be variables I'm not seeing. If you can share your workbook I'd be happy to help further otherwise feel free to post your findings and I'd be happy.