Now it becomes a speculation on LTC price rather than an investment.
With the current difficulty, 110 MH/s can mine around 70 Ltc a day and 490 Ltc a week. That's 490 * 40 = $19600, but we all know $40 is very high and a crash may happens any time. But the opposite may happen too and the price may keep increasing. Anyway this contract is just like buy 490 LTC in 7 days with $18000 ($36.7 per LTC) if the difficulty will not change soon.
The economics are actually slightly worse. Difficultly will increase to around 1770 in the next 22 hours and you will only mine 440 LTC at that rate for a total of $17,600. Now you are losing money.
I agree with you that this is just like buying LTC now.