Approach idle and Flight idle are 2 forms I know of used to increase idle for flight. Approach idle is more like what it sounds like, approach idle is usually a fadec control based on logic (flap and gear position etc).
Flight idle is usually weight off wheels, the company I work for is operating it's first approach idle aircraft and the writeups can be a pain in the ass to deal with because flight mode/condition is usually not defined well in the PIREP. We are all learning.
Also to mention N1 % changes on baro press and temp. I believe somewhere around a 5%increase from ground to approach is an average norm.