I looked up the seat map for today's (May 14th, 2018) flight 78 from DFW-LHR and it is switched to the 9 across MCE configuration from the 8 across PE configuration. Is the Monday DFW-LHR flight 78 always 9 across MCE or is it luck of the draw? How far out do they switch the aircraft so that I can scramble if our seats get moved? One of our 4 seats is a G seat which doesn't exist in MCE. We've put in for 4 mileage and co-pay upgrades to J, any idea as to the odds of getting that? Retrofit schedule for the last two aircraft?