Yes, 'northernboy', it is costly to ship Delivery Confirmed, but whether or not it is TOO expensive is up to you. How much are you willing to risk?
You are right, - a lot of false 'not received' claims, so you will have to make a decision. On higher priced items it is probably a good idea, and sometimes a buyer's outgoing feedback can give you a clue.
And just so you know, items over $250 US are required to be sent Delivery Confirmed with signature. That is so you keep your seller protection.
Oh, and you were aware of the 21-day hold on payments to new and infrequent sellers, yes?