Is there a way to pull multiple custom date ranges at once in Report Builder?

I'm using Report Builder and I need to pull both historical and ongoing monthly data by custom dates for a client that wants to change reporting from calendar months to a 5-4-4 fiscal calendar. I've had multiple reports set up as "Last 2 months" date range and Monthly granularity so I can have this month's and last month's numbers for each line of each report, but I can't seem to find a way to do this if I have to specify custom dates for each month. Is there anything similar to Site Catalyst's Compare Dates option that lets you pull data for two different custom ranges in the same report?

Another possible workaround is to switch to using the Custom Calendar with the 4-5-4 option, but apparently that doesn't work for historical data when you change to it. I might also change back to Site Catalyst but I'd rather not.