A tough math problem?

The kiddos had trouble with this question today. I quoted the question exactly and made up a graph for illustration purposes:

How much more was the difference in costs during year 1 than year 8?

So many students had to ask for clarification. Many of them asked whether the question asked about "Product A" or "Product B." Others listed the price change for each product over the eight years. These were honors 8th grade classes who had trouble parsing this question.