AutoCAD Civil 3D :: Raster Plot Device Causes Labels To Rescale Improperly

Two different plot settings (saved as page setups) will produce different results for exactly the same 34"x22" output.  I have been bucking this problem since I started using AutoCAD C3D. I have a program to adjust the label scaling of my point labels so they are readable in both model space and layouts and when non-raster plotters are used, but now I must adapt it for other C3D labels before I can use them.

Below is my setup for plotting ANSI-D (34"x22") TIFF files at 288dpi.  I have been using this plot device and setup almost exclusively since about 2001.  The output is 9792 pixels x 6336 pixels which is set as a custom paper size to match my 288 dpi resolution (it is 288dpi because that is a multiple of 72dpi which is the default resolution of AutoCAD's TIFF raster output.  It is 72dpi regardless of the fact that the plot scale is specified as 288 pixels = 1 unit or 288dpi).  I must reset the dpi to 288 using image software so the resulting PDF will have a size of 34"x22" instead of 136"x88".  You can see in the preview output I captured that their size difference cannot be attributed to these size differences.  The plots are of the exact same layout showing point labels with only the page setup changed.

TIFF Plot Setup

PDF Plot Setup 

TIFF Plot Output (34"x22")

PDF Plot Output (34"x22")

how to get Autodesk to address or even acknowledge this label scaling error?

Windows 7 Professional 64-bit - Service Pack 1
Intel﴾R﴿ Core﴾TM﴿ i7-3820 CPU 3.60GHz; 16 GB DDR3 Dual Channel RAM
nVidia Quadro 4000; AutoCAD Civil 3D 2013, sp1