Formatting Data Labels in chart

[GregM56]

Hello friends!

I would very much like to be able to include a remote cell in my FORMAT CODE formula when FORMATTING DATA LABELS.

In the Custom Category for Numbers under FormatDataLabels>Number, I use the following code: [Black][>=.5]0%;]Red][<.5]0%; It works fine and colors the labels appropriately based on the .5 target.
Unfortunately, I have to change the .5 every time I change that target number for a chart.

I'd rather point to the cell where that number exists and have it change automatically whenever the number changes.

I've tried: [Black][>='Sheet2'!$C$1]0%;[Red][<'Sheet2'!$C$1]0%;
It doesn't work. The path turns to 0 when I try to add the format code to the Type List << $C$1=.5 in the tab named 'Sheet2'>>

Does anyone know how I might do this if there is even a way to do it?
Thanks for any help.