Fanuc 0i-M Control (2022)

I want to copy some data from the EXEC MACRO P-Data area and use it in my own Macros.
The data is stored in locations #26300 to #26308 and I can see it on the SETTINGS / EXEC MACRO page

I thought I could just copy it to a new local variable like I do other macro values, but it doesn't work
For example, I look at #26300 and it has the value of 6198.000 so I type:

#520=#26300

When I execute the above command, #520 stays 0

How does one transfer data from EXEC MACRO memory to the CUSTOM MACRO memory?