Hi,
I would suggest you should create the hierarchy on fiscal year, something like this,
Fiscal Year
Q1
Apr
May
June
Q2
........
By this way It will be easier to analyze the data in report.
Or you can use offset for current period, Previous period and so on.
But in this case you will have multiple key-figures.
i.e.
1> Sales Qty for Q3
2> Sales Qty for Q2
3> Sales Qty for Q1
Hope it helps!!!!
Thanks,
Bhavin Vyas