Need help with DAX formula for date conditional formatting

[SDolan1999]

Hello! I need help writing a DAX formula that will allow me to use conditional formatting in a matrix to visually show when a rep was added to an account. 

This is a matrix visual, and I'd like the formatting to roughly appear like the below:

This is the DAX formula I wrote:

Format for Start Date =

//Add indicator for start date in the Sales by Rep and Account Table

var PerStart = MAX('Specialist'[Period Sequence Added to Account])

var PerCode = MAX('Dim-FiscalCalendar'[FSC_PRD_SEQ_NUM])

RETURN

IF (PerStart = PerCode, 1, 0)

And set up that the cells should be green if Format for Start Date = 1

I wrapped the to measures in MAX because, without that, I get this message: 

A single value for column 'Period Sequence Added to Account' in table 'Specialist' cannot be determined. This can happen when a measure formula refers to a column that contains many values without specifying an aggregation such as min, max, count, or sum to get a single result.

I should have added that the 'Specialist' table contains several columns, but the two specific to the solution are: a Date column which is date format, and the column with the Period Sequence Number merged into the table in Power Query Editor.

The second table, 'Dim-Fiscal Calendar' is our fiscal calendar table that contains dates, and includes the Period Sequence Number in column FSC_PRD_SEQ_NUM. 

These tables are joined 'Dim-Fiscal Calendar' 1:* 'Specialist'.

[lbendlin]

Please provide sanitized sample data that fully covers your issue.
https://community.powerbi.com/t5/Community-Blog/How-to-provide-sample-data-in-the-Power-BI-Forum/ba-...
Please show the expected outcome based on the sample data you provided.

https://community.powerbi.com/t5/Desktop/How-to-Get-Your-Question-Answered-Quickly/m-p/1447523