From EF...
AC797:
RMKS/TECH STOP BUILT DUE TO HEAVY WEIGHT RESTRICTIONTECH STOP B UILT DUE TO HEAVY WEIGHT RESTRICTION
AC775:
RMKS/PLANNED TECH STOP FOR FUEL DUE PAYLOAD - NOT TO PUMP PAX L
OAD PLANNED TECH STOP FOR FUEL DUE PAYLOAD - NOT TO PUMP PAX LO
AD
Both are 320s, and I don't think it's a range issue, but LAX is experiencing heavy delays due to runway/taxiway construction, according to EF, so perhaps they need to take on more fuel to account for potential holds due to ground delays.