Tax :For Japan to be based on future declared rate in current month

Hi,

Our client has below requirement.

In case of service part sales, currently tax is calculated based on the current applicable rate i.e 5%. But in case this contractual period extends beyond April-14 then for the period April-14 till Sep-15 tax should get calculated @ 8% and if the contractual period extend beyond Oct-15 the tax should be calculated @ 10%. Since currently tax calculation is based on currently pevailing rate, business has to manually take care of additional tax amount.

Business needs a functionality where if services contract period is extending beyond April-14 then for that period amount tax is calculated at 8% till Sept-15 and if the period extends beyond Oct-15 tax for the amount pertaining to periods beyond Oct-15 should be calculated @ 10%