I'd like to count the number of cells with the value "Open" that are not
hidden.
1) =COUNTIF(L:L,"Open")
This does not ignore hidden rows
2) =SUBTOTAL(3,L:L)
This ignores hidden rows but counts everything

What I like is a way to combine these two functions:
1) Since {=SUM(IF(L1:L100="Open",1,0))} works, I tried modifying the sum to
be a subtotal, as such {=SUBTOTAL(9,IF(L1:L100="Open",1,0))} but this returns
a #VALUE error.

2) Is there an ishidden() function? I could do this:
{=SUM(IF(L1:L100="Open",IF(ISHIDDEN(L1:L100),1,0), 0))}
But the ishidden() function does not exist.

3) I tried replacing the ISHIDDEN() with a CELL() function. This gets me
closer, CELL("width") return 0 if the column is hidden, but not if the row is
hidden, I'd need to use CELL("height"). The end result:
{=SUM(IF(L1:L100="Open",IF(CELL("height",L1:L100) 0,1,0),0))}
Does not work since CELL("height") does not work.

Thanks for your help,
Scott