The unanswered SYN traffic to port 23 is much, much more. Especially before the "allow only registered hosts" filter. We are dropping around 80 Mbyte/day of traffic for our /16 subnet due to the address not being registered, so that would be about 20 GByte/day for amprgw....
Of course it is way more than that. I forgot that the about count is only for the subnets within our /16 that are actually routed. That is about 1/5 of our space. So the total "noise" traffic is more like 400 MB/day and would be like 100 GB/day for the entire AMPRnet.
Rob