Help using All while still reading chart axis divisions

Fairly new user, and out of my league just now.  I've got a table of customers and how long they're active with us before disconnecting.  I have a CustTenure field showing that length, and I want to be able to slice that field to show % disconnects up to that length.  I can get that to work in total just using All, my issue is I'm charting that by activation month and can't figure out how to get the All function to react to the month/year of the activation.

Quick example:

Using slicer to pick 1 to 80 for cust tenure

Jan 100 installs, 8 disconnected by day 80

Feb 50 installs, 12 disconnected by day 80

Should chart 8% in Jan, 24% in Feb...but I return 150 as the total installs and the chart doesn't take the month/year into account.

I'm sure I'm just not understanding, hopefully a quick help.  Thanks all.

Kevin