SQL function in report.

I would like to add the following function to the report

In the TCR column I would like to calculate the TCR percentage, but it we use solid SPT(SPT/C) then I would like the TCR value become - N/A

So my equation so far:

<<IIf(<<METHOD.Description>><>"SPT/C",_
<<Format(<<CALC((<<METHOD.Recovery>>/(<<METHOD.Bottom>>-<<METHOD.Depth>>))*100)>>,"#")>>
)>>

But when Method.Description=SPT/C, I would like to give the command to write N/A...

How can I write this command and how can I link them together?

Many thanks...