I'm a little late "jumping in" here, and it looks like you've already got things nicely under control. In particular, you've discovered that the VRDB icon shows separately while a new VRDB is generating even if (like probably most of us, to save space) you've merged the two.
As for the RunInterval setting, Bob's quite right to just leave the ini alone unless you actually want to change the period between VRDB's. RunInverval is just one of many setting-parameters for which avast "assumes" some default value (in this case 3 weeks) if there's no specific line for it in the ini. Probably built right into the exe, I imagine.