The 400 fleet isn't being reduced in QLD, therefore 57.4.1 (c) doesn't apply to the 400.
Another point, just because there are 8 400 slots, doesn't mean that the top 8 300 capt's get first go. The top 8 who meet the command req get them. That inclides any 400 Capt from CNS and any BN 400 FO's who may be higher up than a 300 capt.