The lesson to be learned from all of the above is this: always print in B&W using either Grayscale files or "gray" RGB files (R=G=B). Both these formats will generate the same output and you'll have full control over the tonal range of your images.
If you leave color information in your RGB files, you will still get a B&W print, but you cannot control the grayscale conversion, you can only preview it in Photo shop by converting a duplicate file to Grayscale.
You get much better results if you do your own conversion to gray by controlling the mix of the individual color channels.
For a full color managed workflow, you can profile an Epson printer in B&W print mode using a Grayscale target, which will give you a profile with Device Color Space set to Gray.