<<<"Sorry, you are right. And no, there seems to be no way to make a
named function available to all sheets">>>
This is not really accurate.
You *can* universally assign a named formula to all WS's in a WB with
a single procedure.
In fact ... any additionally added sheets will also contain this
"named formula".
Say you want the formula,
=A1*B1
to work on each sheet of the WB, referencing the cells on the
individual sheets themselves.
From *any* sheet in the WB,
Create the named formula - from the Menu Bar:
<Insert> <Name> <Define>
In the "Names in Workbook" box, type something short, say:
calc
Then, change whatever's in the "Refers To" box to this:
=Indirect("a1)*Indirect("b1")
And hit <OK>
Now, on *any* sheet, you can enter the formula:
=calc
And it will multiply A1*B1 of the sheet you're in.
You can, of course, also create more complicated formulas using this
procedure:
=SUM(INDIRECT("A1:A5"))
=AVERAGE(INDIRECT("A1:A5"))
=VLOOKUP(INDIRECT("D1"),INDIRECT("B1:C10"),2,0)