It is not an extra round. But it may be that they were pointing out that they would have to drag these people back from California or wherever and they were super-busy so it would no doubt extend the trial by a couple of weeks and blah blah blah.
But she really does have to let them do rebuttal.
And repeating what's already been said is basically the point of rebuttal, e.g.:
JW: Good morning.
Dr. Hired Gunn (hypothetical witness name, no connection to any actual witness): Good morning.
JW: Do you recall, Dr. Gunn, when you were here last, you testified blah blah blah?
Dr. Gunn: I do.
JW: In your absence, some upstart sat here and said halb halb halb, which is the exact opposite of what you said, would you agree?
Dr. Gunn: Indeed.
JW: And she said the reason for her opinion was XYZ, plus common sense and evidence. Now that you have heard that information, have you changed your opinion?
Dr. Gunn: No, I am not paid to change my opinion.
JW: kthxbai
Yes.