Can the same file submitted for Fixed Layout conversion also be used for dynamic (flowable) layout conversion? Not likely. Almost all PDFs designed for fixed layout conversions are not suitable for dynamic (flowable) conversions.
Related articles How much does it cost to convert a Fixed Layout eBook? Will my dynamic eBook look like my print book? What are Fixed Layout eBook files? How is Fixed Layout different from a PDF? How should I prepare my eBook file for ePub conversion?