leder - we just used 2300/500 as per the AD (NB Not 930- where does that come from?) and 1400kg. BOTH Pumps off if below those figures, and allow scavenge to start to empty the tank in the cruise/descent phase. No crossfeed used (unless for balance). It seems to me that your procedure (as you wrote it) runs a main pump dry? We just turned off both while they were still 'fuel cooled'..........
You also MAKE an imbalance.
From the AD, with my bolding
Both center tank fuel pump switches must be selected OFF when center tank fuel quantity reaches approximately 1,000 pounds (500 kilograms) during climb and cruise or 3,000 pounds (1,400 kilograms) during descent and landing.