I believe center tank operations were modified by AD 2001-08-24 (and whatever EASA version that usually follows)
“For ground operation, center tank fuel pump switches must not be positioned to “ON” unless the center tank fuel quantity exceeds 1,000 pounds (453 kilograms), except when defueling or transferring fuel.
Center tank fuel pump switches must be positioned to “OFF” when both center tank fuel pump low pressure lights illuminate.
Center tank fuel pumps must not be “ON” unless personnel are available in the flight deck to monitor low pressure lights.”
Which modified the AFM and by proxy SOP that didn’t already do this.
Perhaps the confusion on when to turn it off in flight stems from the ground ops limitation above? The AD says you can run it to the lights in flight.
There’s also AD-2016-18-16 which mandated a retrofit of automatic shutoffs and stuff, but that only applies to the -100 through -500 series.