ERPNext - Deferred Revenue Recognition

In ERPNext Deferred Accounting, if I process deferred entries for 3 months (Jan, Feb, Mar) with 1000 each, and then manually edit the January Journal Entry from 1000 to 500(to calculate actual service consumed days), and then run process deferred accounting for Feb, March . Why does ERPNext add the remaining 500 only to the last month (March) instead of redistributing it to February or proportionally between February and March? Is this standard ERPNext behavior and process.? If not what is the flow to make this entry ? Do anyone help me please?