Hide the math
We're calculating when, as a practical matter, you can start a recall.
It wouldn't make sense to have the recall election at the same time as the regular election for that seat, so what's the latest you can start a recall and still remove them from office in an earlier election?
So, here's the math:
Grey months at the beginning:
No recalls in the first 6 months after they're sworn in (but you can start the 3-week paperwork process to get the Notice of Intent ready)
Grey months at the end:
You can't recall them after they were re-elected. (2 months)
A recall election scheduled within three months of the regular election will be combined with the regular election -- and there's no point having a recall & re-election for the same folks on the same ballot (3 months)
It takes 12-15 months from the start of the recall process until election day. (12 months)
2 months + 3 months + 12 months = 17 months