Mehringer actually makes $450,000. As a comparison here are the salaries for the Pac12 OC's in 2015:
Mike Norvell (Arizona State) - $900,000
Noel Mazzone (UCLA) - $760,000
Tony Franklin (Cal) - $550,000
Brian Lindgren (Colorado) - $455,000
Dave Baldwin (Oregon State) - $435,000
Jonathan Smith (Washington) - $425,004
Calvin Magee (Arizona) - $400,000
Scott Frost (Oregon) - $400,000
Jim Harding (Utah) - $400,000
Aaron Roderick (Utah) - $400,000
Rod Smith (Arizona) - $290,000
Mike Bloomgren (Stanford) - N/A
Clay Helton (USC) - N/A
And here are the B1G OC's salaries for 2015:
Tim Drevno (Michigan) - $800,000
Mike Locksley (Maryland) - $625,000
Joe Rudolph (Wisconsin) - $570,000
Matt Limegrover (Minnesota) - $550,000
Tim Beck (Ohio State) - $525,000
Bill Cubit (Illinois) - $500,000
Danny Langsdorf (Nebraska) - $500,000
Greg Davis (Iowa) - $450,036
Ed Warinner (Ohio State) - $400,000 in 2014
John Shoop (Purdue) - $400,000
Ben McDaniels (Rutgers) - $400,000
Dave Warner (Michigan State) - $387,230
Jim Bollman (Michigan State) - $378,230
Kevin Johns (Indiana) - $332,500
Mick McCall (Northwestern) - N/A
John Donovan (Penn State) - N/A