Nothing really to worry about...miwa still the best domestic act today among albums. (Megadeth...a thrash metal band from stateside, based down south in Los Angeles. As for Oricon rankings, for reference: Suga Shikao #7, Koda Kumi #9)
I'm pretty sure 99.9% miwa is going to get #1. (Unless someone makes a surprise sale, such as in the case for singles, SMAP is #1 on the same day's daily single rankings over NEWS...)