That calculator is probably referring to Neoscrypt now which is completely different to Scrypt.
For a start it is not mineable by Asics any more, because of that the difficulty shot down as well I guess as the network hashrate would have dropped by a large amount.

But I think it is great for some of us that have GPUs lying around as gives me something new to tinker with..

Hashrates vs scrypt are different too. My R9 280x mines scrypt at 715 KH/s, would be lucky to get 60-60 KH/s with this new algo. That's how different it is.