Please post your flow, and debug 4 and 6 values in text format.
There’s a great page in the docs (Working with messages : Node-RED) that will explain how to use the debug panel to find the right path/value to any data item.
Pay particular attention to the part about the buttons that appear under your mouse pointer when you over hover a debug message property in the sidebar.
In order to make code readable and usable it is necessary to surround your code with three backticks (also known as a left quote or backquote ```)
```
code goes here
```
You can edit and correct your post by clicking the pencil 
icon.
See this post for more details - How to share code or flow json
I will then look at the jsonata expressionyou have used
