You are discovering the inadequacies and limitations of musical notation.
You seem to be on the right track with your instincts.
As to "dotted 8ths followed by 16ths", that's often a copyist or typographer decision to suggest or indicate a swing feel.
Swing is any ratio between 50/50 (straight eighths) and 66.6666/33.3333 (triplets)
This is all dependent on tempo, as well.