Re: never heard this before...
Mercedes is phasing out 0W-40 Mobil 1 in favor of 5W-40 Mobil 1. AMG has not yet endorsed the oil. We will continue carrying both weights in bottles but will switch to 5W-40 in bulk.
$4.77 is a good deal. We get requests on a daily basis to ship it out at $5.50 per qt.