Aviation Help Needed

Okay I would be very surprised if anyone knew this, crossing my fingers. This is an extra credit question for my instrument class...

What does the degrees symbol mean on some of the routes off of VOR's on a low altitude enroute chart? For example, most jet routes and such say their degree from the VOR on the line but very few say the degree AND also have the degree symbol. Look at the link provided for an example I found. The Navasota VORTAC on the far left, middle of this chart has various routes coming off of it but the 91 and the 110 both have degree symbols and the others don't, why is that? http://www.mtc.gob.pe …ramas/despachad​or/100.jpg

Thanks for your time.

Only thing I can glean is that those headings are intial on course from the VOR to a place on that airway where the heading changes slightly...?

I'm not IR but I have the IR/Commercial JEP book and the JEP chart examples show the degree symbol on nearly all headings. Maybe it's something native only to NACO?

Yeah I think my teacher said it wasn't on the JEP charts I think.

This is the exact type of question my IFR instructor would ask me. I have forgotten so many little facts like this one over the years. Please post what you find out. Now I can't get this out of my head. THANKS!

Someone on yahoo answers said this...
" on the enroute chart, if the depicted airway radial or VOR / NDB bearing to a fix depicts the degree symbol, that airway or fix also forms part of a published approach or missed approach procedure."

I don't think this is right, does it sound familiar?

Actually my flight instructor just emailed me and said that it isn't written anywhere for sure but that it could be to clarify degrees that could be misread which is logical, both 091 and 110 could be 16 and 011 and the other degrees are fine to read.