HASONEVALUE across 2 time periods

[SonyT]

Hi, I'm still new to PowerBI and still learning how to write measures.

Currently I'm unable to get my grand totals to work.  I have tried using HASONEVALUE but because it is comparing 2 time periods the way I'm writing it doesn't seem to work.  

I have the following calculations (where CY = current year, LY = last year) at customer level:

Diff to LY TotalSales = TotalSales CY - TotalSales LY  
Value = IF (ISBLANK([TotalSales LY]), BLANK(), (([Price CY] - [Price LY]) * [Units CY Total]))
Volume = [Diff to LY TotalSales] - [Value]

The Volume column is calculating correctly at row level ie customer level however the grand total at the bottom of the column is not correct.

So I then tried to use the HASONEVALUE function but it doesn't work in the case where a customer was present last year but is not present this year.  How do I get the grand total to work?  This is the measure I tried to write.

Volume by Customer = if (HASONEVALUE(Table 1[ContactGenericName]), [Volume],
SUMX( VALUES(Table 1[ContactGenericName]),[Volume]))

The table looks like this: 

Hope this is an easy question for someone. Many thanks.

[YJ]

Can you provide the pbix file, if you need to mask out any sensentive info

regards

[SonyT]

Hi, 

Sorry, it's an enormous file with too much info to remove.

Can I provide you with something else to help?

Thank you.