Even in the retail segment, the target date funds don't have "Admiral" options. So you see 0.16% with VFIFX, 0.05% with VTSAX, 0.12% VTIAX, 0.06% VBTLX.
A 3-fund of VTSAX/VTIAX/VBTLX can average around 0.08% for the same underlying asset allocation as VFIFX at 0.16%. That's roughly double.