Their development department might be split into two areas of focus, but there was way more than 2 teams. For example, the "Xenoblade team" has members who worked on Disaster as well as Soma Bringer. Both of which were separate teams during that period. The DS games are also developed by distinct teams. The OG Saga team had nothing whatsoever to do with the Dragonball DS RPG. Monolithsoft is capable of developing at least 3-4 titles at the same time, on multiple platforms. When a game like Xenoblade comes along, they get more resource constrained, but otherwise, it's not as simple as there being two teams.