You are totally wrong brother.
First, $18 to $22 is no where there in any multipool.
Second, there is a factor called difficulty which increases "exponentially".
Now run the numbers in a calculator which matter the above.
The result will be no ROI.
These are not at all profitable or ROI.
I'd ask you to show your work when you make statements like this.
5 Mh of Scrypt mining will make between $18 and $22 a day on a multipool site.
At a cost of $950 these units will ROI in under 60 days.
Even if I am off by a factor of 100% they still ROI in 4 months.
Scrypt difficulty is not increasing exponentially.
The mathematical origin of this word has to do with multiplying a number by itself.
If that were the case than a coin with a difficulty of 1000 this month would have a 1,000,000 difficulty were it increasing exponentially
Litecoin has a difficulty of 7126, for it to increase exponentially it would have to reach 50,000,000
There are no scrypt coins whose difficulty is increasing exponentially on a weekly, monthly or yearly basis.
Perhaps the word you were looking for was doubling?
Like I said, I may be wrong, if even by a factor of several times over, but my math shows ROI.
Also you don't mention during what period you say it won't ROI.
So again show your math and prove me wrong.