Last year's tour ended in June, HOWEVER, the dates were all extremely spread out, with the Asia dates all happening in one month, while her Japan dates were in March, May and June.. but this time the Japan dates are March, April, May and June. Leaving no room at all for ASIA TOUR dates. It's highly likely that during the ASIA TOUR a-nation that they're planning this year, she's gonna do her ASIA dates and then do the final at Yoyogi later on..
http://www.avex.co.jp/e_site/press/2008/070518.pdf
Read this about their '08 ASIA TOUR a-nation plans.