If you take an inch of pitch from many other rows + the 5,5 that allows you to fit an extra row or two.

Compare Lufthansas seatmap for the A320 vs A320neo. The neo has the Smartlav and two additional rows of seats.

http://magazin.lufthansa.com/content/uploads/2016/07/a320_si... http://www.lufthansa.com/mediapool/pdf/08/media_1555228708.p...