Why does this V chord substitution work?

[Axe_meister]

OK blues progression

Bb13 Bb7#9#5 Eb9 Bb13 F7#9#5
I I IV I V I can see how this works, Standard quick change with some jazzy chord voicings

Eb9 E13 Eb9 Edim
IV IV# IV V#dim How do you get here?

Bb13 F7#9#5 Bb13 G7#9#5 Cm7
I V VI VII Is the G7 to C7 just a chromatic pass through?

Gb9 F9 F7#9#5
V# V V What#s with the Gb?

Bb13 G7#9#5 C7#9#5 F7#9#5
I VI VII V


Sounds great, but totally confusing. Damn you Robben Ford.

[tonyteech02]

E diminished chord is a sub for A A7 flat 9 notes are E G B flat C sharp which are the upper structure of a flat 9 chord
next sequence is 1 V 1 V1 11 in b flat
G flat 9 hits a semitone above the 5 and resolves downward a common technique

Eyesight not good in this print but seems OK