Hi! These are my calculations and that is my account. I think generally because single sales aren't frequently updated the numbers have shock value. But even if you lay out calculations crudely you'll get the same if not higher values.
Pure — 65,000
YouTube US (/150) — 250,000
YouTube Other (/500) — 400,000
Spotify (/150) — 10,500,000
other audio* (/150) — 7,350,000
total crude methodology (excl China) — 18,560,000
total broken down by country methodology from the post (excl China) — 17,180,000
if anything this suggests that the numbers I posted were conservative.
in fact, converting Taylor's chartmasters SEA into single units + her 166m pure digital, they implicitly estimate that she has ~1.55BN global single units, and this excludes Chinese consumption where she could have up to 65bn audio streams (it was recently verified she passed 10Bn audio streams on NetEase which has a ~16% market share in China)
let me know if you have additional questions.
Estimated using chartmasters' Spotify * 1.7 artist ratio specific to Taylor