Rabbi Shimon ben Gamliel prepared documents occurring to the practice of the land - regular or bound/tied - but did he have to? Certainly, the different kinds of documents are available as options. Plus, an agreement for kiddushin, based on a dinar of gold -- that turns out to be silver, with all the ramifications (except it seems to be approved). And the question of how precise people are with their words, when specifying details or conditions of a document. Also, a regular document with one witness, or a tied document with only two witnesses -- especially when combined with some other form of authentication, after debating, the sages sent the question to R. Yirmiyah in Babylonia. He demurs, but also answers. At least tentatively. Plus, a different version of what gets sent to R. Yirmiyah - with the question of whether two decisions from two different courts can combine, as it were, to be testimony. Also, a new mishnah! On claiming a lesser amount than an IOU.