ISBLANK() not working with "R1C1" reference

I tend to use ISBLANK(ref) in IF functions as i step through data to see if i've reached the end of the list or am missing a value.

I was getting anamoulous results but when i changed the reference to A1 format works like a champ.

I don't get an error when I use the "R1C1" format but it either misdirecting or simply taking the quoted entry as a text reference and thus returning FALSE because the text RICI is not blank.

Some functions are finicky about the "R1C1" reference but i almost always need to use it as it is the only reference system I'm aware of that allows me to concatenate variables from a FOR/NEXT loop to pick different cells.

but i can't even get this to work without variables as in just entering in a cell

=ISBLANK("R7C2")

it returns false even when the refernced cell is blank. (and i've tested this by using the B7 reference , e.g.

=ISBLANK(B7)

and it works perfectly)

go figure, i hope someone does.

thanx