diff --git a/Koha/Acquisition/Order.pm b/Koha/Acquisition/Order.pm
index 289e4a3115..7f097cc596 100644
--- a/Koha/Acquisition/Order.pm
+++ b/Koha/Acquisition/Order.pm
@@ -503,12 +503,13 @@ sub populate_with_prices_for_ordering {
 
     my $discount = $self->discount || 0;
     $discount /= 100 if $discount > 1;
+    my $unitprice = $self->unitprice // 0;
 
     if ( $bookseller->listincgst ) {
 
         # The user entered the prices tax included
-        $self->unitprice( $self->unitprice + 0 );
-        $self->unitprice_tax_included( $self->unitprice );
+        $self->unitprice($unitprice);
+        $self->unitprice_tax_included($unitprice);
         $self->rrp_tax_included( $self->rrp );
 
         # price tax excluded = price tax included / ( 1 + tax rate )
@@ -536,7 +537,7 @@ sub populate_with_prices_for_ordering {
     } else {
 
         # The user entered the prices tax excluded
-        $self->unitprice_tax_excluded( $self->unitprice );
+        $self->unitprice_tax_excluded($unitprice);
         $self->rrp_tax_excluded( $self->rrp );
 
         # price tax included = price tax excluded * ( 1 - tax rate )
diff --git a/t/db_dependent/Budgets.t b/t/db_dependent/Budgets.t
index 309c949ddf..590c8673f2 100755
--- a/t/db_dependent/Budgets.t
+++ b/t/db_dependent/Budgets.t
@@ -1,6 +1,7 @@
 #!/usr/bin/perl
 use Modern::Perl;
-use Test::More tests => 156;
+use Test::More tests => 157;
+use Test::NoWarnings;
 use JSON;
 
 BEGIN {