If you look at the seven seeds Charlie has:
BYU, OKSt, Washington, and USF it is hard to find a team to move up to replace TN as a 6 seed:
BYU - ONLY top 50 win - #19 TAMU, bad loss #116 Gonzaga plus #72 San Fran, and 82 San Diego
Washington - Good wins #9 Stanford and #10 UCLA - losses to #85 Oregon and #88 Utah
USF - Good wins #30 Ok ST, #40 Chattanooga bad losses #113 Memphis and #69 Temple
OkSt - Good wins #2 Baylor, #22 WV, #32 OK x2, #48 KSU bad losses #107 TCU and 136 ISU
TN - Good wins #5 OrSt, #12 SYR, #19 TAMU, #35 UGA, #40 Chat, #44 Albany, #45 Missouri - offset by 4 bad losses 124 VaTech, 125 LSU, 142 Arkansas, 159 Alabama
Now we all know that those three SEC bottom dwellers are terrible losses, but with the SEC RPI behind them they look better than they should, and the wins against UGA and Missouri look a lot better than they should as well for the same reason, but the same can be said about KSU for Ok ST and TSU and ISU as well and against Oregon and Utah. And 7 wins against top 50 compared to 4, 2, 2, and 1 is 'impressive'. You discount two of them for extra bad losses and it is still 5 vs 4, 2, and 1.