Actually Vandy was 1-2 against mid-majors this year (beat MTSU).
		
		
	 
Just because I'm bored at work, I took the liberty of looking up the record of other SEC teams and their other conference opponents.
Alabama - 4-0 (1 P5 Wisconsin, 1 FCS)
Arkansas - 2-2 (1 P5 Texas Tech, 1 FCS) (Texas Tech & Toledo loss)
Auburn - 4-0 (1 FCS, 1 P5 Louisville)
Florida - 3-1 (1 P5 FSU) (FSU loss)
Georgia - 4-0 (1 FCS, 1 P5 GA Tech)
Kentucky - 3-1 (1 FCS, 1 P5 Louisville) (Louisville loss)
LSU - 3-0 (1 P5 Syracuse) (FCS McNeese State cancelled)
MSU - 4-0 (1 FCS)
Mizzou - 4-0 (1 FCS, 1 indie BYU)
Ole Miss - 3-1 (1 FCS) (Memphis loss)
USCe - 2-2 (2 P5 Clemson & UNC, 1 FCS) (Clemson and FCS Citadel losses)
UT - 3-1 (1 P5 OU, 1 FCS) (OU loss)
TAM - 4-0 (1 P5 Arizone State, 1 FCS)
Vandy - 2-2 (1 FCS) (Houston loss, WKU loss)
So by looking at that list, we have the SEC losing to:
P5 - 4 times (2 of which are playoff teams)
G5 - 4 times
FCS - 1 time (USCe loss to the Citadel)
Statistically, USCe was the absolute bottom in representing the SEC this year with a loss to an FCS school.  However, Vandy and Arkansas are not far behind save the fact one lost to a P5 school and another to a ranked team, though getting skunked in the process.