Sorry, I'm unable to open you file because of your using latest tableau.
Steps to follow:
1. Change FY Start Month->Rick click on date and select Default Properties->select fiscal year start->select month.
Select Sales from Measure and Drop in the Text File and Select select Average instead of SUM.
maybe I do not explain myself well, I need to create 2 calculated fields that give me one value (the current and the previous fiscal year),
in the image you will see the required values that i need,
The calculated fields wil interact with Category and Stated field that could be use by the user,
the attached workbook is saved in version 10.5
the result must be like this image below: