Calculating Growth Percentage from cumulative

Hi, I have two measures:

LineAmountMTD = TOTALMTD(Sum(Invoices[LineItem_LineAmount]),'Date'[Date], Invoices[Type]="AccRec")

PreviousMonthLineAmount = TOTALMTD(Sum(Invoices[LineItem_LineAmount]),PREVIOUSMONTH('Date'[Date]),Invoices[Type]="AccRec")

Now, I need to calculate percentage of growth this month vs last month. I am using this measure:

SalesAmountGrowthPercentage = DIVIDE([PreviousMonthLineAmount]-[LineAmountMTD], [LineAmountMTD])

This does not give me the right output. I might need to just grab the final cumulative totals from first two measures, I guess. 

What am I doing wrong here?