The price for fuel in Nigeria is 0.35 Euro (0.5 US$) per litre or 1.9 US$/Gal. A test in Lagos on a Nigerian Truck showed a saving of 12%. Fright forwarder only make money when a truck runs every day. So 200,000 km (124,000 miles) is a common distance in a year. The consumption before was 35 l/100km and reduced to 30.8 l / 100km = 4.2 l less for 100 km ! With a distance of 200.000 it is a saving of 8400 Litre. So the Trucks save in the cheap petrol country Nigeria 8400 x 0,35 Euro = 2640 or 4200 USD$ in a year. In Germany such a Truck will saver 8400 x 1.1 Euro = 9240 or 13400 USD
It makes even more sense now that the diesel price is now at least 0.67 Euro per liter.