diff --git a/academic_account_interests/models/res_company_interest.py b/academic_account_interests/models/res_company_interest.py
index 1b52c7c7..50a2256d 100644
--- a/academic_account_interests/models/res_company_interest.py
+++ b/academic_account_interests/models/res_company_interest.py
@@ -8,12 +8,10 @@
 class ResCompanyInterest(models.Model):
     _inherit = 'res.company.interest'
 
-    def _prepare_interest_invoice(self, line, to_date, journal):
-        line = list(line)
-        student = line[0]
-        partner = line[1]
-        line.pop(0)
-        res = super()._prepare_interest_invoice(line, to_date, journal)
+    def _prepare_interest_invoice(self, partner, debt, to_date, journal):
+        student = partner
+        partner = debt['partner_id']
+        res = super()._prepare_interest_invoice(partner, debt, to_date, journal)
         if res:
             res.update({
                 'student_id': student.id,
@@ -21,10 +19,66 @@ def _prepare_interest_invoice(self, line, to_date, journal):
             })
         return res
 
-    def create_invoices(self, to_date, groupby=['student_id', 'partner_id']):
-        return super().create_invoices(to_date, groupby=groupby)
+    def _calculate_debts(self, from_date, to_date, groupby=['student_id', 'partner_id']):
+        deuda = {}
 
-    def _get_move_line_domains(self, to_date):
-        res = super()._get_move_line_domains(to_date)
-        res += [('journal_id.type', '=', 'sale'), ('move_id.state', '=', 'posted')]
+        interest_rate = {
+            'daily': 1,
+            'weekly': 7,
+            'monthly': 30,
+            'yearly': 360,
+        }
+
+        # Deudas de períodos anteriores
+        previous_grouped_lines = self.env['account.move.line']._read_group(
+            domain=self._get_move_line_domains() + [('full_reconcile_id', '=', False), ('date_maturity', '<', from_date)],
+            groupby=groupby,
+            aggregates=['amount_residual:sum'],
+        )
+        for x in previous_grouped_lines:
+            self._update_deuda(deuda, x[0], 'Deuda periodos anteriores', x[2] * self.rate)
+            deuda[x[0]]['partner_id'] = x[1]
+
+        # Intereses por el último período
+        last_period_lines = self.env['account.move.line'].search(
+            self._get_move_line_domains() + [('amount_residual', '>', 0), ('date_maturity', '>=', from_date), ('date_maturity', '<', to_date)]
+        )
+        for student, amls in last_period_lines.grouped('student_id').items():
+            interest = sum(
+                move.amount_residual * ((to_date - move.invoice_date_due).days - 1) * (self.rate / interest_rate[self.rule_type])
+                for move, lines in amls.grouped('move_id').items()
+            )
+            self._update_deuda(deuda, student, 'Deuda último periodo', interest)
+            deuda[student]['partner_id'] = amls[0].partner_id
+
+        # Intereses por pagos tardíos
+        if self.late_payment_interest:
+
+            partials = self.env['account.partial.reconcile'].search([
+                # lo dejamos para NTH
+                # debit_move_id. safe eval domain
+                ('debit_move_id.partner_id.active', '=', True),
+                ('debit_move_id.date_maturity', '>=', from_date),
+                ('debit_move_id.date_maturity', '<=', to_date),
+                ('debit_move_id.parent_state', '=', 'posted'),
+                ('debit_move_id.account_id', 'in', self.receivable_account_ids.ids),
+                ('credit_move_id.date', '>=', from_date),
+                ('credit_move_id.date', '<', to_date)]).grouped('debit_move_id')
+
+            for move_line, parts in partials.items():
+                due_payments = parts.filtered(lambda x: x.credit_move_id.date > x.debit_move_id.date_maturity)
+                interest = 0
+                if due_payments:
+                    due_payments_amount = sum(due_payments.mapped('amount'))
+                    last_date_payment = parts.filtered(lambda x: x.credit_move_id.date > x.debit_move_id.date_maturity).sorted('max_date')[-1].max_date
+                    days = (last_date_payment - move_line.date_maturity).days
+                    interest += due_payments_amount * days * (self.rate / interest_rate[self.rule_type])
+                    self._update_deuda(deuda, move_line.student_id, 'Deuda pagos vencidos', interest)
+                    deuda[student]['partner_id'] = move_line.partner_id
+
+        return deuda
+
+    def _get_move_line_domains(self):
+        res = super()._get_move_line_domains()
+        res += [('journal_id.type', '=', 'sale')]
         return res