Well, OT2baseCE is using Openbox/tint2 as a desktop manager, whereas most Pups just using JWM as desktop so that is an increased RAM - not terribly more but noticeable. Also the CE release has a lot of eye-candy, and that uses quite a bit more RAM. That's probably what nnriyer is referring to. At his work PC he should probably use JWM-variant of KL; that one certainly doesn't use more RAM than a PUP. There is nothing magical in RAM usage - simply depends what components you are running and what background processes; some of the eye-candy could be running daemons in background - I don't know. SImilarly XFCE uses significantly more RAM than JWM, but is a more complete desktop environment whilst not really too RAM heavy (like KDE plasma for example or GNOME would be).
KLA-OT2base (the simpler not very pretty original) uses less RAM by quite a bit than the CE variant, but still a little more than a simple JWM desktop would. Depends what you want in the end.
Having said all that KLA-OT2baseCE doesn't use high RAM at all. You should run a Pup (and state exactly which one) and try 'free' command, and do same with KLA-OT2baseCE and post the results rather than just claiming 'high' so that we can see if normal looking results. Otherwise your system may have an issue with KLA such that using more RAM than normal. Generally, like for like in terms of desktop, a KL distro tends to use a bit less RAM than a Puppy when I've tried, but only because we don't generally do copy2ram (though can); the difference is insignificant though, and even if using the bit-higher RAM desktop like XFCE the computer works fine (since nowadays has enough RAM) as long as not a CPU-challenged low-power machine. There are also some KL distros now using simple tiling managers that consume even less RAM sometimes than JWM.