Quick, tell me how wide this range is, just as an order of magnitude:
285368737954–285368783645
Would be a lot easier if I only included the range at the end which had actually changed, wouldn't it?
That's why it's clearer. Now obviously that was an extreme example, but it's also easier to see at a glance that 1,387–9 is just three pages, as opposed to 1,387–1,389.
Quick, tell me how wide this range is, just as an order of magnitude:
285368737954–285368783645
Would be a lot easier if I only included the range at the end which had actually changed, wouldn't it?
That's why it's clearer. Now obviously that was an extreme example, but it's also easier to see at a glance that 1,387–9 is just three pages, as opposed to 1,387–1,389.