Tartly means with a sharp or acidic taste, thus, in this context, it means that Buzz is not happy with the amount of paperwork they have had since the trust took over.
Context: ‘ We 've had more paperwork , not less , since the trust took over , ’ Buzz said harshly .
Hypothesis: ‘ We 've had more paperwork , not less , since the trust took over , ’ Buzz said tartly .

Is the hypothesis incorrect? (Yes, no, or unknown)?