Is the harmonization of International Commercial Law working?

I was studying for the module International Trade Law yesterday, when a thought struck me; there appears to be a pattern forming in the international commercial arena. This is evidenced by the unification and harmonization of the law through mechanisms like the United Nations Convention on Contracts for the International Sale of Goods, the International Chamber of Commerce Model International Sale Contract, various European Union Directives, etc.

But the question remains, is this so called unification and harmonization working? Theoretically, it should achieve its purpose without little or no hitch. However, in reality, the reverse is the case. If anything, it has succeeded in creating more diversity than intended and it is not difficult to see why. The most important reason for this is down to the fact that globally, nation states do not have a single unified jurisdiction when it comes to law. Some have common law jurisdictions whilst others have civil law jurisdictions. Therefore, even if there is a single convention that lays down the law, it is guaranteed that the method of interpretation will be different, thereby leading to different outcomes. Would it would help for clarity purposes if there was a different means for the harmonisation of International Commercial Law? This is something I look forward to exploring during the duration of my course.