I will look into this further--I don't have the resources at home to check
the literature plus I will ask a GI colleague and a neonatology colleague.
 However, re: the subject of mixing formula with less than normal amount of
water to make up 24cal/oz out of powder designed for 20cal/oz--I have seen it
recommended from some well respected places (I think either UCIrvine or
CHOC--Children's Hosp of Orange County, both in California) probably because
it is cheaper than 24cal formula, and what I need to check into is whether
there are any reports in the literature about problems with it.  Potential
problem issues:  1.  increased salt load and decreased water supply, possibly
leading to hypernatremia (high blood sodium or salt)   2.  increased solute
load (overload on kidneys)    3.  increased osmotic load (too many particles
in liquid going through gut) potentially leading to diarrhea.  The commercial
24cal formula that is now available designed for premies has a normal salt
content, normal (I think) water content, normal solute load, normal
(isotonic) osmotic load.
I'll check some references (people and journals) and recomment tomorrow.