Curiosity got the best of me. So I got out of bed to check and sure enough, you are correct my friend . The input is after the ro membrane and just before the DI resin.I have the 4 stage BRS unit with the TDS meter but it has 2 meters, in and out. My in is after membrane and out is after resin. My water pressure is 45-60 and have not needed to change any of the filters after almost a year except resin. Tap is 55 TDS and after membrane it is 3