Pay differences - Acute/Clinic

There has been quite a bit of talk about pay discrepancies on here of late, and I have a question along this vein.  If one was hired for clinic work but was later assigned work on an acute care account, should there by two different LPH amounts paid based on which account you are working in? 

Now, I say "should," but I also want to know if anyone has experienced this and actually gotten paid two different amounts?

When I first started, I was told that clinic accounts were all paid at one wage (rhymes with "door" and "hate" cents per line), but that acute care was paid at a slightly higher wage (rhymes with "jive" and "fine" cents per line).  [I'm being creative as I can't remember if we can say the exact wage amounts on here.]

I doubt that any of us actually get two different wages, or any sort of increase other than what webclock automatically adds in for night/shift differential, but wondered if anyone had successfully gotten it approved.  Or is this just another way the Nuisance rips us off?