Show different line values in Line Column chart for drill down

Hi there.

When I drill down to monthly I want to just see a monthly target line

Also, I just want to see the quarterly target line when I drill down to quarterly.

At the moment I've got both.

'H Fiscal Quarter' is in 'Dates' 

'Date' is in a table called Main:

I've had a look at a similar problem here:

https://community.powerbi.com/t5/Desktop/hide-a-line-but-have-it-show-when-you-drill-down/m-p/511099

Which pin points what I need to do:

Only Months = IF(DISTINCTCOUNT(Table1[Date].[Month]) > 1 ; BLANK(); SUM(Table1[Value])

However, I can't adapt this to work with mine - I've tried loads of different combinations...

So my main issue is how do I adapt it to mine?

I've been working at this for ages - so any response would be greatly appreciated!