Watch the Example 20 online guitar lesson by Brad Carlton from Guitar Lab: Boogie-Woogie

This example differs from all the other examples in this lesson by using quartal harmony which means voicings built using fourth intervals. The chords are A 6/9, A 7/6, A7sus4, A 7/6. These all come from A mixolydian and you have that 3 to sus4 move occuring just as in examples 7, 16 and 17.