In our case, the Over 9000 Swords Pack for UE4 has a lot more demo and example content than the Unity version, which we felt was worth the relative price drop on Unity (30$ vs 40$). There’s also the sad fact that in the over 6 months since release, we’ve only sold a total of 3 units on Unity, so… anything to get us more sales there and perhaps lets us recoup the investment of effort and time we put into the Unity version is justifiable in our eyes.