When in doubt, look at the base together with the melody! When you know what foundation you are standing on (basline/chord) it's easier to determine what's going on in the melody.In the left hand you got an A major chord through the whole bar. In that context, I'd interpret the first chord in the right hand in bar 27 as a appogiatura, the second chord as the resolution (B resolving to A), next one as a passing tone (G#) to the next chord in the progression, B major.
I see what you mean. I find it new analyzing 4 voiced chords as passing tones and something I need experience with. And I guess on bar 28 (my ii in red is wrong) its a G# octave passing tone to the 7th degree of the V (A ocative). So bar 28 would be V7. Bar 27 IV