Yeah, drop rates are definitely different. Systems especially are more rare generally.
That's such a frustrating design choice.
And extra annoying given the wiki gives no drop rate statistics. I would feel better knowing it should take 20 drops average, even if it still took me more than that. Better than it taking 20 drops, but being led to believe it should be 1/3 chance and I am very unlucky.
Also trying to find Oberon Chassis too. Despite getting helmet and system quite close together, I've had no drops from any eximus units in over a week.
Luck is just not with me in this game!