Slacker has three complementary service tiers, from the entirely free Slacker Basic Radio and the ad-free Slacker Radio Plus to the on-demand access of Slacker Premium Radio.
Where 3rd-generation Core graphics were divided into two tiers, the new generation is focused on three, two of which are built for performance over efficiency.
One option, for example, would stretch the tax-band scale by adding one or more new tiers at the top, with tax rates more than three times those in the bottom tier.