Looks like the 757 and 767 differ in multichannel operation. From the 757 engineer trng notes:
One motor operating: autotrim, mach and speed trim, all other modes after hyd failure.
Two motor operating: manual and alternate elec trim.
"Autotrim commands are generated from the FCC first in CMD and processed through its associated SAM. Only 1 autotrim channel (1 SAM and 1 FCC) is enabled at a time, even when operating multichannel.
On a multichannel landing: trim fault in one FCC sequences the trim path to another FCC and SAM, and the "NO LAND 3" message is displayed only after touchdown. A loss of both trim paths activates a "NO AUTOLAND" alerrt." This is the mean difference with a single channel landing.