Filter a calculation based on custom year

I am trying to wrap my head around this, but I cannot get this right. I have custom dates, so time intellgence models don't work. Example, ONLY January 3rd - Jan 20th falls within January. Anytime I use time intellegence, it uses a calendar year. 

I have a calculation that results in a % value, and I simply want a formula that shows me the prior year's %. It seems like no matter HOW I filter, I keep getting the current year. Here is the last code I tried:

Conversion Rate YoY = 
VAR _LeadCount = Calculate(COUNT(Leads[Lead ID]), Leads[Qualification Group]="Partner Qualification", NOT(ISBLANK('Company Leads Report'[Status])))
VAR _WonCount = CALCULATE(COUNT('Leads'[Lead ID]),'Company Leads Report'[Status]="Closed - Won", Leads[Qualification Group]="Partner Qualification")
VAR _CurrentYR= DIVIDE(_WonCount, _LeadCount)

RETURN
    CALCULATE(
        _CurrentYR
        , 'Fiscal Calendar'[Year] = 'Fiscal Calendar'[Year] - 1
        )

Here is what it returns:

I have even tried other filter expressions, but it keeps giving me the current year. I don't know where I am going wrong. 

Thanks!