Download Assistant and "old" downloaded files

Cubase Pro 12, Win10

Due to my slow Internet connection, I prefer keeping the (often huge) files which are needed to install some products, hoping to be able, in case of re-installations, to avoid downloading again.

As the Download Assistant (almost?) always deletes the installation files immediately after install, together with the WIN64/ProductName folder in which it temporarily stores them (I’ve not been able to find an option to force it keeping all downloaded files for good), I usually copy the folder somewhere else before the end of the product installation.

When I need to re-install a product I just copy the ProductName folder inside WIN64 again and then choose “Install” inside DA.
Sometimes this works, with DA skipping the download and directly installing (and then deleting), but sometimes (for example with some .vstsound files) the download starts anyway and the “new” downloaded files are saved in the very same folder, alongside the previous ones, even if they are perfectly the same.

What can be the reason for such a behaviour?
How can unnecessary downloads be avoided?

You have no need for the download assistant if the files are stored on the computer. Simply launch the Setup.exe file as you would for any other Windows program.

What about the “vstsound” files?
Can they be simply launched as well?

Anyway, the Download Assistant does not seem to “detect” the Products which were installed directly.
Which defeats its useful ability to locate and suggest any updates.
Is there a way to force that detection?

I have checked the behavior with version 1.35.0 on Windows 10 with both applications and content (.vstsound files).

The Download Assistant should actually not delete the installation files after install, unless you explicitly select deletion.

It seems that the Download assistant correctly detects already downloaded files once the download/install is started. However, if a checksum does not match, it will download the file again alongside the existing file. This can cause some trouble.