True dimension is 412'-9" what you get from DIST command:

Distance = 412'-9", Angle in XY Plane = 0, Angle from XY Plane = 0
Delta X = 412'-9", Delta Y = 0'-0", Delta Z = 0'-0"

But the current dimension style you are using to put dimensions has 0.039370078740157 Scale Factor:

and distance in each dimension you put with this Dim Style calculated as follows: "Real Dimension" * 0.039370078740157

So you get:

412'-9" * 0.039370078740157 = 16'-3"

If you want real distance in the dim text, you need to set Scale factor in the dim style to 1.

Maxim