Don't be fooled by these numbers. DPI on the print is not the same as DPI in your images. For one thing, Image pixels are perfectly square, and printer dots are round and overlap. If you don't believe this, do some small tests. The HP1050C is very fast in normal mode, and not much faster than the old plotters when in 'Best' mode.
Software settings overrule the buttons on the plotter.
The point of this paragraph is that all of the buttons on the front of the plotter have their functions over-ridden by the printer driver . If you want 'Normal Mode' in 'Monochrome' then set these things when you are in your application's print dialof. It may flash recieving and plotting alternately, or it may do wierd things with the cutter.