So the AMHash shares will only ever make a profit if difficulty increments stay below ~5%. And, even if they do, the profit will be minimal compared to the cost and only achieved after 6+ months.
I'd love to know where you keep getting info that nobody could possibly know.
Is it astrology?
Dude, it's basic math. Run it through one of the bitcoin mining calculators if you want to check for yourself.
As anyone who has mined knows, calculators are absolutely terrible at predicting ROI.
Historically the best priced hardware has always been able to ROI regardless of how many people "proved" it couldn't using calculators.
Assuming you are using a calculator that isn't just wrong in the math it does, the only uncertainty that comes in is from the "difficulty increment" parameter, which is a statement about the future and obviously cannot be predicted accurately. However, you can control it in the calculator and try different values. That's why I said they will only ROI with difficulty increments less than about 5%. If you don't understand that...
I don't disagree that difficulty must remain low for these (and any other miner) to ROI but you cannot calculate ROI with a calculator.
For example if the next 3 difficulty changes were each 0% and the 4th was 20% that would equal 5% average yet yeild much more than if it had been 20% for the first change and 0% for the next 3.