Anyone here have experienced packet loss issues on a SNAP UFB connection with a fritzbox?

We have been having significant issues with our connection and after doing some extensive testing I can see that we are getting 10%-20% packet loss on the connection.

I can replicate this issue pretty easily.  I have enabled Telnet on the Fritzbox and also enabled ICMP response on the Fritzbox connected to the UFB connection.  I also have DD-WRT based routers on my Snap VDSL connection at my home and at our office which has Iconz providing the internet backbone.

So no client computers are involved in this testing and all ping tests are run by telnet into the routers and between the routers. So the routers are:

ICONZ DD-WRT
SNAP VDSL DD-WRT
SNAP UFB FritzBox

Here are the results I see:
ICONZ DD-WRT <-> SNAP UFB FritzBox  6%-20% packet loss when pinging in either direction
SNAP VDSL DD-WRT <-> SNAP UFB FritzBox  6%-20% packet loss when pinging in either direction
SNAP VDSL DD-WRT <-> ICONZ DD-WRT 0% packet loss when pinging in either direction

I have been discussing with Snap since Wednesday, but getting this resolved is moving very slowly.  I was told this was being escalated to Tier 2 response, but have not heard back.  They said they ran a slope test and it looked fine and also that they sent pings every few seconds and it seemed OK.  However, while on the phone with Snap I asked the tech to ping the Fritzbox and they also saw 11% packet loss on ICMP pings.

Clients connected to the fritzbox are having their remote desktop sessions intermittently drop and experiencing problems with web browsing (Gmail web interface timing out, web pages timing out, etc...).

I am really struggling to figure out what the problem is here especially since it is UFB and this is my first time working with a UFB connection in Auckland.

Anyone have any ideas/suggestions about what this might be?

Can you have a dirty/noisy fibre connection?  Network congestion? Internal routing or hardware issue somewhere in the Chorus/Snap network?

I have asked Snap if they can provide a new Fritzbox so that we can determine if it is a failing/faulty Fritzbox.  However, they said I have to wait for Tier 2 support and I'm still waiting for a reply.

Anyone have thoughts/suggestions/insights would be most appreciated.  I'm at my wits end here and our ability to work and do business is being majorly impeded here.

Thanks!