To be fair, according to RockGamer's site, there was a 2 month release difference between the different Amberian Dawn tracks:
"River Of Tuoni" and "He Sleeps In A Grove" came out in March
"Valkyries" came out in May
"Incubus" and "Shallow Waters" just came out in July
So, the more that RGS submits into the review process, it hopefully increases the chances of getting the Amberian Dawn songs out in a more timely manner to meet demand.
Also, is Amberian Dawn the only band to have announced their existing discography coming through the RBN?