Consequently, she was decelerating. Next, thrust levers were not unlocked before about 15 seconds after autothrust disconnection, while she first climbed, then still at 84%.
When levers were unlocked, PF manually applied 100% N1, for about another 15 seconds, before reducing thrust when PNF asked him to go down...
Nope!
Sorry disagree.
The PF didn't apply the appropriate procedure which was "THR LVR... MOVE" he instead disconnected using the disconnect push-buttons and because the thrust levers were in the climb detent the thrust increased immediately to climb thrust.
Later he realises his mistake... "we are in climb" and reduces thrust manually.
Had he wanted to climb he would have left it alone.