Just to chime in, basically dev has to prepare patch, if for example you bump version of UE or something like that or you simply deemed delta patch to be too much of an hassle, you can submit to MS whole thing again as a patch. And don't run any delta after you submit.
This is to large degree fault of Unreal engine, since 4. There are some checks in place to do checksums and patching its not really straight forward process automated process, so if you have other shit to do quick, this is an easy way how to do it, especially with smaller team.
Besides caps are thing of the past and game is not yet launched, so it basically does not matter how much data do you push for pre-load.