If they need 6 wheel truck to transport 2 wire slings (one sling is 1 meter long ,another is 2 meters long, both coiled) that would be real revolutionary mean of transportation. 11T and 15T means SWL, that is a weight of the cargo can be lifted, not a weight of the wire sling. Nobody is making slings that heavy. They can fit that into ordinary car trunk. Each sling is not heavier than 10 kg.
Perhaps we are talking about amphibious 6 wheel truck we can use for crew change from the field, in that case the price sounds reasonable.