Another data point and phone booking fee reference.
Making the most of my soon to be lost Platinum status I requested two separate international seats releases.
The first release request was for F seat SYD to DFW on 5 August 2019 (yes way out but no F seats on that day). This was a gift to my brother for his 50th birthday and his first international flight above Y. I’ll give him this gift next week

. Anyway after 10 minutes the seat is released and booked. No phone booking fee imposed.
The second release request was for J seat SYD to DFW on 9 August 2019 for myself which I booked after an opportunity openned up in Colombia around that time (hopefully no problems there when travelling). This time after 5 minutes waiting for the release I was given a reference to check back. About 1 hour later received a booking e-mail and the next day the points deducted and co-payment taken from credit card. Again no phone booking fee imposed and I didn’t have to ask.
I also previously used this release request feature for a JNB - SYD J seat back for travel during peak January period, so really have benefited a lot from the option. To think when I was first time WP I didn’t even know this service existed but I’ve made up for it the second time a WP and this the likely third and last time a WP, a great benefit in my opinion.