it's understandable that avex uses more money on kumi nowadays. Ayu's already well known in Japan, and kumi (at that time) wasn't that super popular. If kumi had the potential to be a more popular singer (which now she does), why not investing more money on kumi?
for ayu... I can see a bigger promotion will come if avex thinks the song will be a big hit. At this stage ayu's still enjoy doing her own music, so no complain for a smaller promotion than kumi (hey they still have promotions, it's not like you dun see ayu at MS or MF or whatever!!!!). As long as ayu and we the fans are happy, things are fine
