I look at ID and QXP as end-use applications. As such, I generally maintain all my Excel and XML files as separate entities. In your case, once the expressions are done in Excel, replacing the data if it updates isn't a big issue.
However, while I have never used InData, I do use EmData's XData in QXP often. InData has a lowercase function (downcase), can be used to strip spaces (trim), concatenate (simply &), etc. You may desire to download the trial version.
Take care, Mike