Looks like you assign an LWEIGHT setting to each object, and don't actually use a plot style table for line weights.

And on the "vertical" layout, the scale is so teeny tiny I'm not sure you really need to print line weights.

Are you wanting to really use LWEIGHT settings on the objects to plot? Let us know, since that means PLOT WITH PLOT STYLE is doing nothing more than converting your colors to monochrome as you've asked the program to do.