Mate you need to give us more info bud.
For instance if your tap is 160, what ro are you using and what size di vessel.
My tap tds is much higher than yours. (Cant recall of top of head, but about 280 or above). I have a simple 450gpd ro combined with a booster pump, my tds is down to about 009. I use a 4.5 ltr di to polish it to 000. But other times i use just the water from ro. At 009 or even slightly higher, its still good for cleaning spot free.
So with your tap tds being much lower, you should not be spending that much on resin pending your set up