RE: Allocation of Revenue account
You can use Recurring journal for such case. You can find recurring journal under Financial management --> Periodic Activities --> Recurring Journals.
All you have to do is to create a new line within the recurring journal page with recurring Method = balance, Recurring Frequency Daily if you want to do it on daily basis or keep it empty so you can run it whenever you need it, and select G/L Account 405000. Keep Amount empty and lick on the action button Allocations. Set line for each allocation as you propose :BS1-50% and BS2-30% and BS3-20% .
This recurring journal can be configured as daily or any other frequency that you see suitable.
Please let me know if this answered your problem