You are about to spend significant amount of money on a DONE4, the TA fee is such a little part of that, probably your Uber to/from the airport may be more.

with QF you will wait on hold for ages, have different agents trying to work it out, run risks of ticketing issues, get a run around with seat allocations and just have overall poor and frustrating service, and have to pay some telephone fees. They are just not trained for this.

with a decent TA you will have the reverse of all of that.

KF