At least with the Microsoft software that I use, FTP preserves the date
of the file so that I can see at once how old a document is; HTTP
rewrites the date to be today, losing that information.
For I-Ds, not really an issue (but for RFC, that would be a serious
impairment).
You might enyoy switching to rsync, which both preserves the date, and
is a lot faster since it knows how to skip the ones you already have.
The usual version for Windwowsseems to be cwrsync:
https://www.itefix.net/cwrsync
R's,
John