Thank you azrobert, you are my new hero! I just plugged those settings in, saved and rebooted.
I have not been answering before it is blocked, but it rings simultaneously both here and at the spam service, so I hear the first ring or two regardless of whether it is a legit call or a spam. Delaying the ring like this should allow the service to check CLID and decide whether it is a call that needs to be answered by it or by me. If the spam service hasn't caught the call by the second ring, chances are that I want to answer it myself.
I work at night, and I get a ton of spam. The filter service has been a blessing, but I made some changes to where my number is hosted (ported it from Number Barn to Google) and ever since, spam calls have been slipping through for a ring before getting caught by the filter. Delaying the ring a bit should resolve the problem, I think.
Thanks again, I really appreciate it.