I just realized the plat and completion percentage don't work properly (yet), if it's within a date range.
If you start a game in 2015 and plat it in 2016, it will count towards your plat percentage in 2016, but only the trophies earned in 2016 will count for completion.
On the other hand, if you play some dlc 2016 from a game you've finished earlier, both percentages will suffer.
I'll work out a solution, I'll probably only count games started within the requested time period.