this is probably the one of the longest on going scam I've ever known.
I know right. After all this time. Well you know what they say in crypto that if the roi is way shorter than the competition then its too good to be true 
The "roi" is set by what people are willing to pay for the MHS (was KHS) being sold. That has nothing to do with scrypt.cc being a scam or not. The prices are very low per MHS because the yield is very low. It was set to 20% after the hack and never restored. Prices just adjusted to the lower return. It is a free market. That is all.