How are the EA Funds default allocations chosen?

The recommended distribution between the four focus areas of effective altruism is as follows:

Can someone please show me where the scentific reasoning behind this particular distribution is justified in discussions, presentations, or litterature?

Does it follow the logic used here by Benjamin Todd (80.000h) and here by Robert Wiblin (80.000h)? Or is there more to it?

I hope you enjoy your summer!

Kind regards,

Peter