As I've sold the 2.0 D4D Avensis 5dr that I had a few years ago I don't have the manuals but I'm sure that the max permissible towing weight was actually less that the 85% match weight.
I might well be wrong though
The newer model had a higher towing limit with the introduction of the 2.2 D4D engine. We considered that model series but instead changed the Avensis for a RAV4 with the same 2.0 engine but with 4wd and a 1500kg towing limit. It tows a 1450kg Lunar T/A very well!
I haven't seen any figures for the model just released but as it appears to be a bit heavier again than the old Avensis I would expect the towing limit to increase.