Also regarding this issue, another 2 questions:
If Tagmatic troops are present in the army, can Tagmatic Commanders join Thematic Troops ? For example, can an Elite Themata Cavalry unit be led by a Tagmatic Commander, provided the army contains Tagmatic troops (such as Cataphracts) ?
Can Varangians (which are Tagmata) be led by Tagmata Commanders or Generals ? Because it says Byzantine commanders are mounted and only Thematic Officers can be fielded on foot, which means Tagmata Infantry units such as the Varangians cannot be led by Tagmata Officers, since mounted officers can not join infantry units.