Active versus flattened documents with eSignLive process

I've not been able to find documentation which explains the differences between flattened and active documents. Mostly, we are interested in the legally viable significance of each type of document within the eSignLive process so we can better understand the process mechanics we need to bake into our business. One scenario is that we presently download the active documents and evidence summary for each transaction for safe keeping and store in a secure location outside of eSignLive? If we've already downloaded and stored the "active" documents, then what's the significance of keeping archives? Can you point me to something or provide some narrative about the significant differences between these documents as it pertains to the UETA and eSign Laws? Has eSignLive produced any best practices that help customers ensure we use the product in a manner that helps us maintain legal viability in court? Thanks, Todd