diff --git a/scipost_django/finances/admin.py b/scipost_django/finances/admin.py
index 8da21fc79d49a528cff3c204500284f5368ef5ed..a56da3b0247c69fff534afb67b55a2caab38ac27 100644
--- a/scipost_django/finances/admin.py
+++ b/scipost_django/finances/admin.py
@@ -19,11 +19,15 @@ from .models import (
 
 class SubsidyPaymentInline(admin.TabularInline):
     model = SubsidyPayment
-
+    autocomplete_fields = [
+        "invoice",
+        "proof_of_payment",
+    ]
+    extra = 0
 
 class SubsidyAttachmentInline(admin.TabularInline):
     model = SubsidyAttachment
-
+    extra = 0
 
 @admin.register(Subsidy)
 class SubsidyAdmin(admin.ModelAdmin):
diff --git a/scipost_django/finances/models/pex_coverage.py b/scipost_django/finances/models/pex_coverage.py
index 4f68c987eed695787e76b203f002b5ae8a205e54..cdc846b7bd09e3b91e3254929e20109b1555dec0 100644
--- a/scipost_django/finances/models/pex_coverage.py
+++ b/scipost_django/finances/models/pex_coverage.py
@@ -40,5 +40,5 @@ class PublicationExpenditureCoverage(models.Model):
     def __str__(self):
         return (
             f"€{self.amount} for {self.publication.doi_label} "
-            "from {self.subsidy.organization}"
+            f"from {self.subsidy.organization}"
         )