you will need to modify this slightly but hjopefully you can see what im trying to do.

copy file nan.dbf to tmpnan.dbf && make a copy of the nan table
use NAN in 0
use tmpNAN in 0
Select tmpNAN
APPEND FROM c:\tmp\arr TYPE xls && append everything from the xls spreadsheet into the tmpnan
sele nan
append from tmpNan for recno() > 6 * append from the tmpnan into the real nan filtering the records as required


Its far easier to get all the excel records into a table and then filter the data as you need to.