The clock accrued some noticable delay, being almost 2 seconds late. The calibration ended up being nudging the error from -6.19 PPM to -6.37 PPM. This was for 4 months, so it'd extrapolate to being 6 seconds later per year.

Battery is at 3.011 V, but I measured values down to 3.003 in the past weeks. (It was at least 5 C colder then.)