Pebbles on a flat EPDM roof

[4Q]

I'm currently building a posh garden shed (build thread coming soon when I have a few more pictures) with a very low slope flat roof covered in one piece of EPDM rubber. Does it need gravel on top, there seems to be conflicting advice on the internet. It's bonded completely to the boards underneath so doesn't need ballast.

[4Q]

Thanks Roofer