GMC shipping policies are replaced when using 'My shipping settings are complex...' option

As reported here - 
https://wordpress.org/support/topic/gmc-shipping-policies-replaced-by-add-in/

The third option of setting 'My shipping settings are complex....' doesn't work, it appears to do the same thing as setting a 'flat rate'.

What it should be doing is in effect making no changes whatsoever to any shipping policies in the GMC.

Thanks
Rob