Everything being lost would be a symptom of different field names.
Even if the data is changing, the names of the fields should remain (or be mapped to) your fields in Sense.
With the possibility of the backend data source changing from file to Excel (or database), it would be best to implement an n-tier architecture where data is loaded from your source into a QVD and that file is loaded into a data model QVD where other QVD sources are (could be) joined and finally your App or UI that binary loads the data model QVD.
This also allows for different developers to work on the various pieces simultaneously.
Your UI App will then be easier to manage keeping the field names the same regardless of the downstream changes.