I have a similar problem with well water. However I installed a pre-filter ahead of the softener to take out sediment when I built the home 2.5 yrs ago. This helps the softener perform a bit better and I'm sure contributes to overall RODI performance. I need to heed AZ's recommendations as well and get a booster pump.

I have similar pressures as you and a really heavy iron content in my water. I chew up a pre-filter every 3 weeks however have not noted any iron staining anywhere. It is about that time that the water pressure in the home is notably reduced. The home that I demolished at this location had iron stains in the sinks and toilets from the heavy iron content.

I also plan on looking into the DI resin he recommends. Good luck and keep us posted.