I don't know if and from which version this syntax will/would work for SQLServer.

It is my understanding that the VALUES syntax is only applicable starting with SQL Server 2008.

could you try to run these two in sql server directly w/ values binded and see if there is any difference?

I can try but that would be an entirely manual process of 500 bind parameters. My only access to run this via SQL Server would be through TOAD and not the Enterprise console.

P.S. I have no idea if Sql Server supports that tuple syntax or not, if someone could verify it would be great.

SQL Server 2008 and later supports EXISTS/VALUES combination. The tuple syntax used by Oracle 9i isn't supported and based on my research, the EXISTS/VALUES syntax is SQL Server 2008 and later's equivalent.