What I meant was that other risks do not justify a higher offered ROI. Exchange rate is a risk but not relevant to the pricing of the product due to the law of one price (spot-future parity). That leaves future difficulty (expected mining income) as the only factor that determines the price, which must result in zero expected ROI at inception for similar reasons. Buying 250 LTC (expected) for 300 LTC is obviously a bad deal, while the other way around is bad business (plus it would create an arbitrage opportunity). So the price must equal the expected coins mined with the contract, so that the NPV equals zero (or at least head in that direction).

Only cloud mining contracts demand upfront payments (that shifts the credit risk to the customer), so that justifies a discount (ROI greater than zero at inception). This is why cloud mining is a shady business in general, because a discount means that the company is getting a bad deal. So even legit cloud mining companies are either exploiting their customers, or running a very poor business..