I tried using an anki plugin (https://ankiweb.net/shared/info/932119536) to display the pitch accent of words I'm learning. Some of the words I tried entering showed multiple possibilities for the same word. For example, it shows that 二つ rises on た, but may or may not drop つ. Its the same with 三つ. 夜間 can either start high and drop after や, or rise on か.
I am looking for the "officially correct" accent of Tokyo Japanese. I saw an official pitch-accent book by NHK somewhere. I'm thinking about something like that.
So my question is, do some words really have more than one possible accent? I know the accent can be modified for any word by the situation, emotion, etc..., but will an official pitch-accent dictionary list multiple accents. The plugin I used does it automatically (although it claims they originated from NHK) so I'm worried there could be errors.
Lastly, I do not plan to memorize the pitch-accent for every single word in Japanese. I'm only using this to get the basics.
I know that was off topic, but I thought I should add it in for the sake of those who pop up out of nowhere to criticize study habits:)