Dropbox: are the submissions appended to the same spreadsheet like it is when I view the submissions report in my account?

When I have a form save to Dropbox...are the submissions appended to the same spreadsheet like it is when I view the submissions report in my account? 

No, submissions are stored as PDF files in their own folder: https://support.jotform.com/help/77-Upload-to-Dropbox-with-JotForm 

Let us know if you have more questions, we will be glad to assist you.

Oh my, that is not helpful. What is the use case for that? Why would anyone want each repose to a form be in individual pdf files rather than continuing to add the responses to the same spreadsheet? 

If you want to have responses in a spreadsheet, then we recommend you using Google Spreadsheet integration: https://www.jotform.com/help/228-How-to-Integrate-Form-with-Google-Spreadsheet