I just crossed the 12-month mark so I can now reflect on the experience of building a time machine.
So far I’ve had no problems with the monthly shipments. The U.S. distributor seems to be very competent and regularly charges me the monthly rate each month.
The email notifying you of payment also includes tracking information. My packages have arrived 4-6 days after each time. I believe they are dispatched from Pennsylvania so shipping is pretty quick.