Perhaps you can bring a fleet that exceeds the 20 unit pop cap, but only 20 units can be on the field at once. More than that may not be managable. Think about it, yeah, having 100 ISD's at once would be cool, but there would be no way to manage them all. For instance, in RTW, you can only have like a dozen units at a time. More than that would be unwieldy. However, more units can enter as some are destroyed/retreat. So like, say you bring in a fleet of like 15 ships, and as some are destroyed, more enter the battle as reinforcements.(like in RTW) So, a fleet of 100 ships would defeat a fleet of 30 ships, but not all of them would fight at once. ...at least, I hope so.