each to their own, but i stay away from detailed direct contact with applications through OLE, especially with applications like Excel, that have their own crazy/automatic things happening differently at each different version. the most i'd do and have done is either export a csv or excel format file or (at maximum) open a new excel file and worksheet and stuff data into rows, without formatting etc. even then (the latter case) you get strange automatic conversions of numbers into dates etc because excel thinks that was a good thing to do.
also be pre-warned that excel is the only commercial spreadsheet that uses floating point math, so that numbers beyond a few decimal places (in some cases) end up as an approximation instead of the decimal you put in.