I'll chat to Critical Care about how they arrived at this. At the moment my reports show that we have good headroom on the network to be able to provide excellent throughput. Let me check the exact times from your tests and compare to my reports from the last few nights.
I agree with your comment that the IPC issue is not as bad as it was.
However, I concur with DrJohn that in the evenings, things become less than ideal, to the extent that WA and other accounts (apparently VOX from the results I've seen posted on this forum) outperform WA capped accounts.
That's just what I and a few others seem to be experiencing. Perhaps others are luckier.