I would let the Red arrows of the left and right MC go, and consider just Red arrowing the center MC to act as an AMC on attack. There is a fatigue/condition/spatial price for arrows.
You have your STs already covering the spot where you put the left/right MCs with reds, so its overkill, it's a bit like chess or checkers. Covering attack areas is somewhat similar to Zonal Defense, but the reverse, being or attacking where they are not. Check this out if you haven't already done it, a simple good piece on Zonal by Accyrover (View Profile: Accyrover - Top Eleven Forum)
http://forum.topeleven.com/tutorials...-part-1-a.html
Arrows have a weight to them, overkill on arrows will start to appear around the 70th to 75th minute. I am sure you would have noticed, the fitter team will usually make the difference at this juncture of time. Arrows are not freebies, the players have to cover more ground and thus will be less efficient and take more time in getting back to their default position.
If you can get the desired GOAL with less arrows then use less arrows!
Of course I cannot see the individual attributes of all of your midfielders, so again my two cents is based on all your Ms being equal.
P.S. By the way blueing your ML/R will stop their GOALs against you if they have attacking AMs/Ms Wingers!
"Defend where they are! Hit 'em where they ain't!" ~ P.L. Willis