Hmm, I just threw some numbers in my brain concerning this..
so 1 LTC in 12h with 2.7MH/s.. Thats 10 LTC in 12h with 27MH/s and 100 LTC in 12h with 270MH/s and 1000 LTC in 12h with 27 GH/s
So if I understand correctly.. They have almost 40 GH/s now.. Thats roughly 1700 LTC in 12h or 3400 in 24h.
They do this promo for six more days which gives:
6 * 3400 LTC = 20.400 LTC
20.400 LTC * 16 $ = 326.400 $
So they spend 326.000 $ AS A PROMO

WTF ??!?! Are they cooperating with Coca-Cola or so ??
You need to remember, CEX is the company behind this. They have become massive. $ 326,000 is nothing but advertising/marketing costs to them... there's no way pool operators can compete when companies this large get involved.
Also, in saying that, I highly doubt GHash/CEX will execute a 51% attack on LTC. It would destroy their reputation and they would end up losing millions, Bitcoin commodities are far more profitable in the long run than taking over the LTC network for a brief amount of time...