Ok Dr Who, i'll keep your juxtaposition complex in mind in future.

Bad news, i can't get the 2nd file to alert Northbound at all. Simulated the entire section plus extra before and after:

Start [S26°56.375' E152°59.579']: image

Finish [S26°46.134' E153°02.658']: image

One alert only on the Southbound route at very commencement as shown: image Only AustraliaSection1s.gpi loaded for both directions.