Don't let GW's crafty labeling fool you, my friend. There is nothing chemically different about a wash, AFAIK. To me, washing is a verb, not a noun. You can mix a wash with anything, it just requires sufficient dilution. Just like GW Glaze paints aren't anything special either, just a crafty name given to diluted paints. I think that inks tend to be higher gloss than normal acrylic paints. That is probably the sole difference. Seriously, don't put too much stock in the names of these paints-they are all just diluted differently, some may be more matte or gloss or satin, but the same hold true for different colors of regular (non-ink, non-wash) acrylic paints.
So there is nothing about a wash that programs it to fall into recesses without overly tinting the entire surface-other than dilution. So if you dilute an ink similarly, you should have similar results. Some inks from some companies are very high in pigment. This, combined with glossiness, means that you may have to dilute it A LOT.