Bright streak with Aveda coloring questio

Hi.  I have been getting my hair colored for years (light brown is my natural color but the greys are coming in really fast and furious).  I get my roots touched up every 2-1/2 weeks.  I have had my hair a nice auburn but it seems like whenever it's colored I have a bright, and I mean bright streak where my part is.  To me it's very noticeable.  Is there a way to prevent this?  Maybe they leave the color on too long (45 minutes plus).  They won't color over all my hair because they say it would take too much color every time so they will only do it every other time.  Could they blend in where they cover the grey better to keep me from looking like I have bright orange skunk hair?

Thanks for any input I can get.