I love transcribing music. It’s not a strictly musical skill.
For me, transcribing inner lines is often as much about hearing the logic of the voice leading and harmonic progression as it is hearing the precise notes. I can infer the correct notes based on my understanding of music. It’s much how a crossword puzzle is as much a logic puzzle (“What 8-letter word has a X in the second position and ends in ING”) as it is a language or knowledge puzzle.
The only problem comes when innovative music defies traditional logic. I’m transcribing a Gene Puerling arrangement, and he almost militantly avoids following logical musical choices. The surprises are what I love about his music, and what makes his music so difficult to transcribe.
But for most music, treating it like a logic puzzle is often a more successful way to transcribe it quickly and accurately. Use your knowledge of how music works to more quickly discover how this specific music works.