The Empire had set up its second defense line, where mechas were the main force. The number of mechas wasn't much higher than before, but there was a significant increase in the level of mechas present.
There was an abundance of Noble Mechas; according to the existing performance levels of the Federation's mechas, most of these were composed of Mountain-viewing level mechas. Although they were only one standard level higher than Conventional Level Standard-type Mechas, their collective combat power during group combat had improved by more than a single standard level.
The Independent Groups, capable of avoiding the Empire's main defense line, had no way to bypass the defense line formed by the highly mobile Mech Corps.