My inferences are that a petition in that district comes at the start of the school year, and they take the end-of-year test.
The time spent (1 hour a day all summer) was to do all of the next year's curriculum. It sounds like they did all of it, instead of pretesting the material themselves and compacting where warranted.
This was not how acceleration happened for my kids (1 under Everyday Math, 1 not) in a different system. "Adventures" in Math Acceleration in our house starts with scheduling and ends with asynchronicities in things like handwriting and organizational skills.
