Hi,
1. Is there any automatic control in SD wherein once we create an SD invoice, it will be automatically posting FI documents?
Posting Block in the BILLING DOCUMENT TYPE configuration allows the system not to release Invoice to accounting
you have to manually release them using VFX3 transaction code
2. What are the implications of changes in price at the invoice level?
If you are changing manual price at billing level, definitely there will be discrepancy between sales order and Billing
If any reports were extract from VBAK and VBRK then you can see the difference
otherwise there is no impact except in reporting
regards,
santosh