Discrepancy between Rooftop PV and World PV API values



First time user here. I’ve been playing with the data, especially on https://api.solcast.com.au/rooftop_sites/my-site-id/estimated_actuals vs https://api.solcast.com.au/world_pv_power/estimated_actuals on 100% efficiency for comparison purposes.

I entered exactly the same data, e.g. capacity, lat, long, azimuth, tilt, loss factor=1. I found that the World PV averaging 91% of my rooftop site values. Why is that? Is there hidden factors such as temperature, assumed inverter loss, etc?

Note: my account is free hobbyist account, if that makes any difference.