The InChi and Inchi keys generated by CambridgeSoft differ from the ones published on Wikipedia.
You can download a test tool available from IUPAC and confirm we match the IUPAC´s test tool.
1- Download the stand alone InChi program (stdwinchi-1.exe) http://www.iupac.org/inchi/download/index.html
2- Run the structures you are getting a different result from and confirm they match with the CambridgeSoft results.
3- Be aware that there are cases where the InChI test tool doesn't match *itself*, with none of our software involved at all, so there may be cases where we also do not match.