BFTV, are you talking of the average for the last 5-day-period? It seems to me that the slower rate of refreeze in the 81-10-period is because the rate of refreeze is slowing down as the extent grows. In the latest years (including 2015) the extent is lower and the rate of refreeze still higher, at this point.
From the posts earlier in the thread, it seems to me that the curves are converging somewhat in Mid-November. 2015 is heading "up" towards many of the earlier years, but still being among a cluster of recent years, a little below "the pack".
It would be interesting if Espen could include some more years like the earlier posts, at least for one day, to get the broader picture.