"Write to Spreadsheet File" has to be high on the list of confusing node names - maybe just a bit less confusing than "Number to Decimal String."
"Write to Spreadsheet File" really means "Write to a Character-delimited Text File" (I guess that would just about THE original spreadshseet file) and not "Write to an Excel Spreadsheet."
("Number to Decimal String" really means "Number to base10 String" ("Number to Fractional String" is what you want if you want to represent a number that has numbers to the right of the decimal place.))
It's confusing, but this is where ctrl+H is your friend...
I apologize for the joke thing. It was difficult to tell if you were joking or not because it was difficult to assess your LabVIEW expertise from the code you shared. It would probably still be a good thing to read up on the basics, though.