Custom Tooltip Troubles - Displaying different % ?

Struggling with custom tooltips displaying the wrong percentage and hoping someone can support me.

For the below chart, PowerBI default tooltips display two percentages which is going to confuse my users (Turning off %GT interferes with filter interactions, so leaving that on). To get around the double percentage, I want to use custom tooltips, cards or a matrix visualization to display the percentages in the below chart: 

Looking at the custom tooltip page, percentages are correct when using % of column total, where % and sample are a weight variable.  

However, when I hover over my stacked bar chart visual, it displays everything as 100%: 

I'm almost quite certain I'm missing something simple here, and hoping someone can point it out. 

Many thanks in advance!