I saw the video......
Most lawn care guys down here sharpen or change blades once a day...... They change the blades then sharpen the set that came off at a later time.... It pays to have several sets to save on down time ..... I noticed the second one you took off was badly worn and chipped / buggered ...
I'll make a video on how I sharpen blades and post it on you tube later on in the future... I am making a series of videos now on overhauling a 6.75 Briggs........
Plus Tard Mon Ami ~!~!