I am pretty new to growing plumeria, but I do know that any Singapores cant be forced into dormancy, the only thing that I do know is that it will probobly kill it. If I were you, I would keep it in front of your sunniest window, that way you wont have to worry about it dying and it will grow larger and bloom more!

Last year was my first overwintering my plumerias and I had 1 dwarf singapore and another unnamed plumeria. I didnt really have good light in my apt, so I was planning on letting it go dormant. As soon as it got to freezing outside, I brought them in for good and let them alone, didn't water and just let them be. Around february, I did have to defoliate the plant, because I was worried that it had gotten a fungus, but come summer it woke up and didnt seem fazed. In my experience, it isnt too hard to overwinter and let them go dormant, and it works to leave the leaves on or defoliate. Cutting the leaves off does cut down on bugs/possible fungusnes, but as andrew said, it will definitely have a head start in the spring if you are able to leave the leaves on. Good luck!

Last winter I put most my DSPs in the garage with the rest of the plumeria. I defoliated them first. The garage stays above freezing. Come spring I pulled them out with the rest and fed and watered them and away they went. No problem. I left my largest outside on a covered patio. It lost most its leaves but was hardy at about 30F (measured in the yard) about 6 times for about 6-8 hrs ea.