Artists on Apple Music will earn a bonus payout of up to 10 percent in royalties for all songs that are also available in spatial audio. That’s according to an update sent to record label partners and seen by 9to5Mac. Quoted by Music Business Worldwide, it says that starting with January’s month-end payout, “pro-rata shares for Spatial Available plays will be calculated using a factor of 1.1 while Non-Spatial Available plays will continue to use a factor of 1.” Pro rata refers to the…