There is a serious misunderstanding here; I wished you had e-mailed me first. I will try to clarify for you and other customers (It is probably my fault not to explain in more detail something that seems obvious to me but not to people that use my products for the first time):
1. The advantage of preheating the empty mugs is that while your tea or coffee are brewing, you already have the hot mugs waiting.
2. It is obvious that if you preheat two HotSmart Mugs at the same time you need to increase the preheating time; I hope you did that (1:30 minutes for two mugs should have been enough). To distribute the energy equally, the mugs should be positioned on opposite sides of the turntable (I was assuming basic knowledge on how to use a microwave oven, maybe I shouldn't have).
3. The HotSmart Mugs DO STAY STILL HOT after 30 minutes AND... There is nothing that impedes reheating the tea or coffee in the HotSmart mugs if you want to. There is NO NEED to pour tea into another mug to reheat :) That would have never occurred to me (I repeat: it is my fault). It is good that HotSmart Mugs have an A-Z GUARANTEE, isn't it? You got your refund. :)
4. By the way, you sent me an e-mail through the amazon System asking if you could reheat the tea in the HotSmart mug but... you sent it many days after you returned your mugs and got your refund. Why?