Yes, I think you're reading that right. All of the section covered by clause 8 has to be read together, so it's 25% of the eligible voters, and then you look back to subclause 8(2) in terms of age requirements. It is possible to have one vote, and if it's defeated the first nation could also, at a later time, propose a slightly different MRP law and move to another vote as well.
On May 9th, 2013. See this statement in context.