I’ve checked the code of both DTHs and they do not change the wakeup interval so the device is waking up at the same interval with both DTHs. The regular DTH doesn’t create an event every time it wakes up which is why you only see those events when using the plus DTH.
The checkinterval value shown in the IDE has nothing to do with how often the device actually wakes up. The DTH sets that value to the interval it thinks the device should check in and SmartThings uses it to determine when to ping the device and mark it offline.
I think I read somewhere that attaching it to anything metal will drain the batteries.