The Westbury, Wiltshire-based bulk haulier took 10 Actros 6x2 trucks earlier this year, and M&N's latest five new units are all the same 2448 models, with the 476bhp 12.8-litre straight-six engines driving through Mercedes PowerShift 3 automated transmissions.
All also have the flat-floored BigSpace cabs and their mid-lift axles have been fitted with 17.5in wheels, which not only free up extra space on the chassis for hydraulics packs, but also save a 250 kg payload.
M&N Transport further reduces weight by specifying its tractor and trailer combinations with Alcoa Dura-Bright alloys – although against that, the firm has gone for roof-mounted Kelsa light bars and upgraded entertainment systems.
According to director Mike Burton, M&N Transport was running vehicles by two other unnamed manufacturers when it bought its first two Mercedes-Benz Actros in 2009, just as the recession hit.
The arrival of its latest five Actros allowed M&N to sell off its last non-Mercedes-Benz tractors.
"We were very happy with the fuel efficiency of our Euro 5 Actros, but the Euro 6 trucks are even better," says Burton.
"They're averaging just shy of eight miles to the gallon, which puts them at least a quarter of a mile and. in some cases. up to half a mile further ahead."
M&N has also now started a trial of Mercedes' optional Predictive Powertrain Control system, which Burton believes promises further mpg savings.
PPC employs 3D GPS mapping to read 3km of topography ahead in order to optimise truck speed, braking and transmission, and hence maximise fuel efficiency.
"Rygor have been a breath of fresh air," adds Burton. "They treat us properly ... and are very accommodating."