My thanks to Engineer48 for bringing to my attention the following
Section 5 of the contract see image states it only requires the signature of IH to grant an extension of time to the Validation period. Since IH signed said extension Rossi and Leonardo completed the contract in the stipulated time. The argument that other signatures are required is invalid.
As always to verify the image text here is the original source via the court docket is here:
So that you can peruse the originals
Kind Regards walker