Anyway, what is your experience and background in sizing softeners and I'll include troubleshooting them for someone other than yourself; if you've ever actually done that. Tell us Bob, and if you don't, I say you are only using the spec sheets that you have mentioned reading a few days ago.
Look how few posts of yours are in reply to anyone with problems and compare them to your posts that in essence say I'm wrong about something.
I sold a WS-1 to a master plumber for a customer of his in a 135 seat steakhouse and then after he ordered it he called to apologize to me for saying I was wrong (just like you are here) and wanted to change from the WS-1.25" to the 1" two days after it had already shipped. He insisted as you are here that the 1" wouldn't deliver the gpm he needed. That was until he got his plumbing sizing books out and looked up what I told him.
IMO Bob, that is some of my actual and factual field experience and the unit is a year old next month. The only problem with it was someone left it run out of salt last summer. It is a 6.5 cuft (16 or 18" tank IIRC) WS-1.25" unit on 1.5" main with city water, reduced by that master plumber of 35 yrs from 2" (Peter).