Yes, be careful not to use fills too often, and use p a few different fills. Normally of course fills are put in the last measure of verse, bridge, or chorus. A fill often is a signal that a different part is about to happen. If you are doing this in your DAW, modify the rhythm of the notes or the notes themselves. So one fill might just be a rack tom, and a floor tom. Some fills could be some extra snares, or kicks in the last bar of verse. another could be a full roll of al toms.
Some fills might be extra notes in the last 1 or 2 beats. Might also be the whole measure. There is a psychology to music. The brains job is to find patterns, I personally feel, there is a 'satisfaction' in figuring out the patterns, whether it be chord structure, melody, rhythm. But if the music continues with the same patterns, the brain starts to look for something else to analyze, and looses interest. Fills in a song, are surprises and indications of what is to follow. That is why interesting songs often 'layer' new parts in as song progresses, to keep you picqued as to what might happen next.
You need enough repetition for the brain to find patterns in the music. But if this continue to go on and stay more of less static.. The brain begins to lose music.
There is also a value to repetition, like 'Billy Jean' by Michael Jackson. You get drawn into the hypnotic rhythm. Jackson maintains that basic structure much longer than expected, but he 'fools with your anticipation' not with drum fills, but with his vocal stylings, of 'ooh', huh, breaths, growls, etc. He also knew that his dance moves would be so surprising and enticing, the strong rhythmic/harmonic bed he created would keep you 'hypnotized' to.
Congratulations on taking the Naval school of music chorus.. I have perused it's content. It is very thorough. If the statements above 'strike a chord with you'.. (ha ha).. Thee is a great book, 'This is your brain on music'. A valuable insight into music for a songwriter, composer, even performer. There is also a free course at Coursera.com.. I believe it is called something like 'Music as Biology'. I took it several years ago. Coursera tries to get you to pay for it, and you get a 'certificate' (it's not college credit, or anything) You can also do something like 'audit' it for free. You get no teacher feedback, only other students, which may or not be helpful, depending on what they get out of the course. The teacher who gives the lecture, is pretty boring, but the information and insight you gain, will give you lots to think about regarding composing, playing, or even just enjoying music
Leonard Bernstein gave a few lectures on music at Harvard many years ago. You can find this for free, on the internet and also is very insightful. You don't have to be heavy into music theory or study, to get a lot out of this.