Calculate sales forecast using two tables

Hi,

I am trying to figure out a formula to calulate sales projections using two different tables. I created a relationship between the two tables via my "Item" column.

Table 1 contains previous fiscal year sales data

Table 2 contains expected percentage increase per month per ITEM

I created measures totalling each of my monthly sales data in Table 1 i.e. a measure for Total Sales in June, Total Sales in July etc. E.g. FM19Apr = CALCULATE(sum('Sales History'[Units Sold]),FILTER('Date','Date'[Fiscal Year]="FY18"),FILTER('Date','Date'[Month]=4)) 

I am trying calculate the sales increase per ITEM per Month. Note, I also have a data table.

E.g. Table 1:

E.g. Table 2: