Go into Design View on the subform, and in the subform's properties find the setting called "Data Entry".
Changing that to "Yes" will change the subform's behavior.
From then on all the subform do is be clear and ready accept data for new records. After a record is entered, the subform is cleared and will be ready for another brand new record.
This option is available for any form.
I would update the other two subforms with this setting. Easy, and no VBA necessary!