I'm sure you already did it a dozen times, but I just reconfirmed all your numbers and angles.
What I like to do, is get my azimuth dialed in, then raise and lower the lnb to look for my bird.
I've always had pretty good luck getting the dish aimed right.
And I like using a $10 meter, turning on 22khz tone if necessary.
But do consider that the dish may be twisted or the LNB arm may be off-center just a wee bit.
What I do, is take a 25¢ compass and lay it on the side of an 18" level.
Mine is an aluminum I-beam shape. On its side, it looks like an H.
Rotate the compass 'till the N needle points to N
Maintaining the needle on N, align N and S on the compass parallel to the I-beam
This is trivial to do by eye, as long as you have a steady hand.
Now the level is set exactly to magnetic N/S
Holding everything steady, rotate the compass body 'till the S end of the needle is pointing to 107
If you are unsteady, you could tape the compass at this point, but I don't.
Now, rotate the whole assembly 'till the N needle points to the N, again.
Your level will now be exactly lined up with 107.
Using the long (18" in my case) level, it's easy to see if your dish is pointed correctly.
Alternately, you could sight along the level and find a distant object for future alignments.
I have a distant power pole I use for one of my dishes.
Do the above procedure several feet from any metal that would attract the compass.
BUT MORE IMPORTANTLY, hold the level -level-, sight along it and look for an interfering building or tree!
You should be able to see if you have a problem using this technique.
I don't have a $200 professional instrument for this job, so I improvise.
If the ancient Egyptians could align multiple pyramids to a degree or so, we can surely do as well !