Billboard, Nielsen Soundscan, IFPI, the Official Charts Company, etc. all use album equivalents, too.
The reason album equivalents seem to favor older albums is because they've had time to add catalog units. In today's climate, even a flop single can manage 100M streams (~67k albums) and with even "flop" singles like "Pretty Girls" drawing in well over 3M streams a month, it'll be no time before streaming overcompensates for the shift in the market. I mean, just about any artist with a big hit can get 1B views (~667k albums) for one single. Justin alone has pulled almost 1B streams in a month, and his album has only been out for two full weeks. And unlike catalog album sales, which only seem to favor rock and male-oriented artists, streaming lifts the catalog sales for all non-country artists.
10,000,000 people > 9,900,000 people. You could argue that the second is more impressive and a bigger anomaly, but the point of following charts is to get an objective, unbiased opinion of how many people an artist's music reaches.
Do you have any information on the SEA total for this year?