This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Not entirely sure, but this may be caused by your use of an argument index. I believe if you don't specify one, it will use some internal index, and that it increments for the next use. When you specified an argument index, it looks like this internal index doesn't change.