The line item extractor has a tickbox for considering multi line headers, how does this work in practice? do i need anything special in my labels if a header actually goes over multiple lines?

I've got the following headers:

my label is currently set up to look for "Ext. price". I've tried regex for excluding "inc. gst", tried then also including "ex. gst", tried secondary labels, no matter what change I make it never detects it.

Currently it looks like this:

And my results: