There were two separate tranches of these warrants sold.

46 million warrants were sold to investors that give the right to buy 34.5 million shares at $2.60.

40 million warrants were sold to Al Mann that give the right to buy 30 million shares at $2.60.

A price of 0.41 per warrant equates to $0.55 for the right to buy one share of MNKD for $2.60

Since the warrants are at the money, the delta should be about 0.5, so a reduction in strike of $0.10 is worth about $0.05.Therefore if the strike was $2.50, they should traded for about $0.61.

The Aug 2013 $2.50 strike last traded at $0.60, so you are getting a couple of extra months for $0.01.The reason that it is only a penny more expensive is probably due to liquidity.

The Jan 2014 $2.50 strike last traded at 0.81.

So, it does appear that they are slightly cheaper than the exchange traded options, but not by that much.