It was reaching 8:30 earlier. Demand is just to run like earlier, nothing extra asked. It is very much possible but railway is adamant. Strongly doubt some vested interest in delaying the train on both direction.
Swap is better, but not required to swap also, 12623 is reaching PGT at 4:00 Island can reach 4:15 and 16527 can reach 4:25. So that the train can reach SRR at 5:00, CLT 6:30 CAN 8:25.