That makes sense, except that it would have to be the prosecution rebuttals, rather than closing arguments (since of course they've already given those). Last time I think these were short, limited to only about 30 minutes or an hour for each lawyer.
No: technically, what the prosecution has already made is
opening arguments (which often confuses people, since opening arguments come near the end of the court process, as opposed to opening
statements, which come at the start).
The order of play in arguments (which commence after the evidence/testimony phase) is as follows:
1) Prosecution opening arguments
2) Civil parties opening arguments
3) Defence closing arguments
4) Prosecution and civil parties closing arguments.
The defence do not get a chance at rebuttal, and only get one chance to present an argument - therefore this one chance is termed a closing argument. The prosecution (and IIRC in Italy, the civil parties) get two "bites at the cherry", primarily because the burden of proof is upon them. They therefore have the chance to address and rebut the defence's closing argument. As a result, their two separate "goes" at argument are termed opening argument and closing argument.
In the last appeal I think the jury actually started deliberating immediately after the final court hearing, on the 3rd (when Amanda and Raffaele spoke) and the verdict came late in the evening of the same day. So in theory the verdict could presumably be delivered on the 20th, depending on how long they take to deliberate.
In the Hellmann appeal, prosecution closing arguments were (I think) made on 30th September. I think that this is when the clock started on judicial panel deliberations. It's true that Knox and Sollecito were permitted to make statements to the court on the 3rd October (the day of the verdict), but I don't think these were considered material to the nature of the deliberations.
Since prosecution closing in the Nencini trial appears (per Vogt) to be slated for the 20th, I think it's improbable that verdicts will be delivered any time before the 22nd. I think it's very likely that the verdict will come between the 22nd and the 24th, since the 24th is a Friday.