فَإِذَا زَادَتْ وَاحِدَةً: فَفِيهَا ثَلَاثُ شِيَاهٍ.
Translation: When it increases by one beyond two hundred, three animals become due.
When the flock increases from 200 to 201, the obligation rises to three animals. This parallels the earlier transition from 120 to 121.
The next express boundary is 400, so counts of 250, 300 or 399 remain in the three-animal bracket.