In comparing the British Library's manuscript with that of the RRIISS, other differences also become apparent - first, short sections of missing or rearanged text, and second, the method of writing numerals. 

First, we observe sections of missing or rearranged text. In these examples, the yellow highlighted text is what is missing from the RRIISS, and the green highlight indicates text that has been moved within the page can be seen is in the beginning of the document where there is a list of podestà and the dates of their tenure. The manuscript has:

In del cui tempo fue l'oste del comuno di Pisa a Serraia. Messere Alexandro de Calveli podesta anno I M.CC.LII. Federigo Imperadore mori lo di dela festa di Sancta Lucia, MCCLI. Nella indictione VIIII idus Deciember a di XIII Diciembre. Messere Angielo de Sancto Gustatio podestà mesi VI MCCLIII 

Meanwhile, the RRIISS has:

In del cui tempo fue l’oste del Comuno di Pisa a Serraja. Federigo Imperadore morì lo dì de la festa di Sancta Lucia MCCLI. nella Indictione IX. Idus Deciember a dì [I3]. di Diciembre. Messere Alessandro da Calvoli Podestà anno uno. MCCLII

Why are the podestà listed in a different order? Why is one left out? These questions are probably unanswerable, but they do indicate that the RRIISS editor used a different manuscript than the one held in the British Library now. While the missing one could just be a line that the editor forgot to transcribe, the reordering of the list seems to be a little harder to pass off as transcription error. 

There is another example is on f. 12v of the British Library's manuscript:

lo conte Ugolino torno a casa sua che istava per la signioria dela podestaria e della capitanaria al palasso del populo e vouse chel conte Ugolino che per l'oficio delapodestaria e de la capitanaria stava al palasso del comuno tornasse a casa

The RRIISS renders this:

lo Conte Ugolino, tornò a casa sua, e vuosse, che ’l Conte Ugolino, che per l’officio de la Podestaria , e de la Capicanaria stava al Palasso del Comuno, tornasse a casa

Here we see text that British Library's manuscript has, but is missing from the RRIISS again. This text in the manuscript starts in the middle of one line, takes the whole of the next line, and a portion of a third line. This is even harder than the previous example to explain away as simple transcription error from the British Library's manuscript. The missing line does not begin in the same place as what is included, nor begin with that same or similar wording as what appears in the RRIISS. This is even stronger evidence that the RRIISS comes from a different manuscript.

Another difference between these two textual witnesses which, given that we have yet to find the manuscript used by the RRIISS editor, raises questions concerning the editorial process, is the discrepancy in the way numbers are written in the text. Numbers with a four (4) in them in the manuscript are written as "IIII " where the RRIISS has them written in the more modern "IV." This could be because the editor of the RRIISS adjusted them according to contemporary convention in order to make the chronicle more readable. Another option is that the two different manuscripts were written by different scribes who used the different methods of writing a Roman four. Both of these possibilities raise questions about the different treatments copying the same text, differences either between two different scribes in the thirteenth century or between one thirteenth-century scribe and eighteenth-century editors. In either case, why would one choose to use one Roman numeral set over another? To twenty-first century eyes, the "IV " is easier to read, but this is because it is what I am used to seeing. It also prevents confusion about the numbers. With the four rendered as "IIII," it can be difficult to distinguish between a three and a four when reading. This suggests that the RRIISS editor changed the numbering in the RRIISS for the ease of the reader.

These discrepancies are notable because they show convincingly that the RRIISS version relies on a different manuscript. They also demonstrate that the RRIISS version is inferior to the British Library's manuscript due to these discrepancies and the missing text mentioned on the previous page.