That is the common inference. The VDSL during coexistence is on lower power, and hopefully after the 18month the higher power setting may improve speed. But the rate limiting step I believe is still distance and copper quality.
Many say that is just an NBN excuse and their experience has been that speed did not improve post coexistence.
People have reported an improvement in speed and stability by getting new copper in their house and removing copper joints and branches.
As your speed is greater than 25/5 NBN will say your connection is a success and there is nothing wrong with it. Worth getting a cabler in to examine your house copper pair
Have you also checked your actual “line speed” - get this by logging into your modem.
I guess I will know in a few months time. Apparently there is some maintenance being done at our NBN node next week. I doubt that is the 18-month period end work as my records show we are now at 15 months since initial availability.
I have changed the internal wiring slightly so that my modem is at the first wall point in the house and no longer loops to to the others. The oter home phone points now connect to the phone outlet on the modem. Practically, I replaced the original RJ11 that looped from incoming phone line to additional in-home phone outlets with a 2-gang plate with two RJ11 sockets. The incoming NBN terminates there on one RJ11 socket. And the second socket connects to the other analogue phone points in the home. That way my home phone base station does not need to be collocated with my modem and router.
My report of approx 50/20 speed is from the model sync rates, not from speedtests of actual data throughput. The model never syncs better than low 50's. I originally contracted for 100Mbps NBN, but as I could not achieve better than 50, my RSP removed the "speed pack" from my invoice and refunded some of the extra I had paid. My invoice shill shows I am contracted for 100Mbps, but only paying for 25Mbps, while I get approx 50Mbps. My perfoamance is good enough for my needs, and not paying a premium for additional performance is ok by me. But I won't be complaining if it improves slightly in a few months - not that I will notice in practical terms anyway.
Next move will be to ditch the home phone service, which will happen when our youngest child eventually gets a mobile phone. We keep the home phone so she can make emergency calls (to authorities or to us) when she is home alone. She will likely get her own mobile phone soon and we will no longer need a land-line phone in the home.
Then I can ditch the dodgy telco provided modem and directly connect my NBN service to a real router via VDSL interface. The telco modem is only in the path to provide the land-line phone, with my real router providing all my home LAN connectivity (3 separate VLANs, multiple PoE WiFi APs with multiple SSIDs etc.).