A first update with my actual experience. Arriving from NRT on UA, the clearance of immigration was very fast. On the VOA desk, there were 3-4 people in front of me. I had to fill in a form, which took 5 mins and one photo, and then another 10 min wait at the desk. The officer asked me for a departure ticket, so I showed him the printout for my ticket to REP, and that was fine. They told me that I can do VOA as many times as I want. Hopefully the wait will be similar the next 2 times. I will report back. Also, the visa is free until March 31. I looked into changing the ticket to RGN to include only a transfer, however the times did not suit me very well, given I want to maximize the sightseeing.