You're invited to merge added stuff in the "newer" version on the right, into the "older" version on the left. The "Synchronize Dirs' command in Total Commander, and in particular its Asymmetric flag, expects you to copy from left to right instead. That is the more intuitive order in my mind: I grew up on the command line writing "cp source target".
That's just an opinion. But say you're looking at an EDP directory comparison that reports the left version of a file is newer. You zoom in on the pair of files. Now the items unique to the newer file are labeled as "Deleted"?
On the other hand, while TC imposes a preferred order of copying, EDP lets you merge in whatever order you prefer. It just labels differences in a biased way. Why not label items "left only" or "right only" instead? Well some people (including me) have trouble remembering what is left and right so that's not better.
Okay, up to now, all this ranting ends up in me suggesting to add "left-only" and "right-only" to the "Added items" and "Deleted items" in the Colors page of the Settings dialog. But then I turn to the status bar and see a box with the Added color listed first, then a box with Deleted. The left box is trying to help you realize what stuff is in the right pane only, right? Right?
