Are you speaking of the timezone as stored on the smart plug itself. I think the schedule on Kasa may be based on your current zone but the plug follows what is stored internally on the plug.

I was thinking one is a 50 watt equivalent and the other a 60 watt equivalent.

One thought might be smart Amazon buttons to launch a scene. I currently just use an Amazon Dot and Spot to turn the lights on or off outside schedule time. Not sure if the buttons are available...

Not sure if it will (IFTTT). What I use is Gideon and set up a time offset x number of minutes after Sunset (or a set time). Gideon will talk to IFTTT and TP-LINK.

Check if the timezone is correct. Mine did this once and the timezone was incorrect.