It is fine to have multiple hidden values inside a form. The problem is that you have multiple hidden values with exactly the same name but different values. I am not sure how you retrieve your data on your server side. You could use different name for different hidden value.
Pretty cool idea. Though I haven't tested this idea yet I like it.
Normally when I submit values under the same name my server builds a stack. What you're saying is, this is not a common method of using forms. Some browsers might only send one value with that input name.
I think that's good enough to be solved. I'll figure it out.