If you are copying data from one Excel worksheet to another, then I'd probably suggest using Excel VBA, which is very powerful.
KM does NOT offer any direct Excel support, so you would need to either use copy/paste, or use AppleScript to get the data from the Excel source into KM, and then back to Excel. But then why go through KM?
Just use AppleScript.
Excel also has a lot of power worksheet functions, like VLookup, that make it easy to copy/link data.
I had been using VLOOKUP and VBA until my superiors decided to not allow unlocked sheets. Now I am forced to do other. I am looking into Python and AppleScript. I am not versed in either so steep learning curve.