Transfer Queue is slow / what is Pre-transfer?

I've used older versions of SmartFTP with stunning success, and would like to continue using it, but some changes in newer versions have created issues. When SmartFTP goes through files in the transfer queue, there is a "Pre-transfer" action it performs on every file, even when the filesize matches the destination. The previous versions I used did not do this, and just instantly skipped right through when filesize matched. That extra second per file is not acceptable for my purposes, as it adds up to a huge delay when dealing with an FTP server with a very large number of files, most of which already exist locally. And by huge delay I mean days or weeks. I've tried other FTP clients, only to find further disappointment... it seems nothing can match SmartFTP's intelligent queueing.

So, for the sake of keeping my sanity, I ask: what exactly is this Pre-transfer thing, and if possible, how can I disable it?