diff --git a/src/main/java/org/folio/fqm/service/EntityTypeService.java b/src/main/java/org/folio/fqm/service/EntityTypeService.java
index b6cec4a9..31007f14 100644
--- a/src/main/java/org/folio/fqm/service/EntityTypeService.java
+++ b/src/main/java/org/folio/fqm/service/EntityTypeService.java
@@ -126,7 +126,11 @@ public ColumnValues getFieldValues(UUID entityTypeId, String fieldName, @Nullabl
 
     if (field.getSource() != null) {
       if (field.getSource().getType() == SourceColumn.TypeEnum.ENTITY_TYPE) {
-        return getFieldValuesFromEntityType(entityType, fieldName, searchText);
+        EntityType sourceEntityType = entityTypeFlatteningService.getFlattenedEntityType(field.getSource().getEntityTypeId(), null);
+
+        permissionsService.verifyUserHasNecessaryPermissions(sourceEntityType, false);
+
+        return getFieldValuesFromEntityType(sourceEntityType, field.getSource().getColumnName(), searchText);
       } else if (field.getSource().getType() == SourceColumn.TypeEnum.FQM) {
         switch (Objects.requireNonNull(field.getSource().getName(), "Value sources with the FQM type require the source name to be configured")) {
           case "currency" -> {
diff --git a/src/main/resources/entity-types/orders/simple_purchase_order_line.json5 b/src/main/resources/entity-types/orders/simple_purchase_order_line.json5
index f5acd9a3..f7f467ed 100644
--- a/src/main/resources/entity-types/orders/simple_purchase_order_line.json5
+++ b/src/main/resources/entity-types/orders/simple_purchase_order_line.json5
@@ -380,7 +380,6 @@
       valueFunction: 'lower(:value)',
       source: {
         entityTypeId: '58148257-bfb0-4687-8c42-d2833d772f3e',
-        columnName: 'cost_currency',
         name: 'fqm',
         columnName: 'currency',
       }
diff --git a/src/test/java/org/folio/fqm/service/EntityTypeServiceTest.java b/src/test/java/org/folio/fqm/service/EntityTypeServiceTest.java
index f61a8939..6166c287 100644
--- a/src/test/java/org/folio/fqm/service/EntityTypeServiceTest.java
+++ b/src/test/java/org/folio/fqm/service/EntityTypeServiceTest.java
@@ -176,7 +176,7 @@ void shouldGetValueWithLabel() {
       .id(entityTypeId.toString())
       .name("whatever")
       .columns(List.of(new EntityTypeColumn().name(valueColumnName)
-        .source(new SourceColumn(entityTypeId.toString(), valueColumnName)
+        .source(new SourceColumn(entityTypeId, valueColumnName)
           .type(SourceColumn.TypeEnum.ENTITY_TYPE))));
 
     ColumnValues expectedColumnValueLabel = new ColumnValues()
@@ -208,7 +208,7 @@ void shouldReturnValueAsLabelIfIdColumnDoNotExist() {
       .id(entityTypeId.toString())
       .name("the entity type")
       .columns(List.of(new EntityTypeColumn().name(valueColumnName)
-        .source(new SourceColumn(entityTypeId.toString(), valueColumnName)
+        .source(new SourceColumn(entityTypeId, valueColumnName)
           .type(SourceColumn.TypeEnum.ENTITY_TYPE))));
 
     when(queryProcessorService.processQuery(any(EntityType.class), any(), any(), any(), any()))
@@ -239,7 +239,7 @@ void shouldFilterBySearchText() {
       .id(entityTypeId.toString())
       .name("this is a thing")
       .columns(List.of(new EntityTypeColumn().name(valueColumnName)
-        .source(new SourceColumn(entityTypeId.toString(), valueColumnName)
+        .source(new SourceColumn(entityTypeId, valueColumnName)
           .type(SourceColumn.TypeEnum.ENTITY_TYPE))));
     String searchText = "search text";
     String expectedFql = "{\"" + valueColumnName + "\": {\"$regex\": " + "\"" + searchText + "\"}}";
@@ -256,7 +256,7 @@ void shouldHandleNullSearchText() {
       .id(entityTypeId.toString())
       .name("yep")
       .columns(List.of(new EntityTypeColumn().name(valueColumnName)
-        .source(new SourceColumn(entityTypeId.toString(), valueColumnName)
+        .source(new SourceColumn(entityTypeId, valueColumnName)
           .type(SourceColumn.TypeEnum.ENTITY_TYPE))));
     List<String> fields = List.of("id", valueColumnName);
     String expectedFql = "{\"" + valueColumnName + "\": {\"$regex\": " + "\"\"}}";
@@ -378,7 +378,7 @@ void shouldReturnCurrencies() {
       .name("currency-test")
       .columns(List.of(new EntityTypeColumn()
         .name(valueColumnName)
-        .source(new SourceColumn(entityTypeId.toString(), valueColumnName)
+        .source(new SourceColumn(entityTypeId, valueColumnName)
           .name("currency")  // The special FQM source uses "currency" as the name of the currency value source
           .type(SourceColumn.TypeEnum.FQM))
       ));
@@ -405,7 +405,7 @@ void shouldReturnTenantId() {
       .name("tenant-id-test")
       .columns(List.of(new EntityTypeColumn()
         .name(valueColumnName)
-        .source(new SourceColumn(entityTypeId.toString(), valueColumnName)
+        .source(new SourceColumn(entityTypeId, valueColumnName)
           .name("tenant_id")  // The special FQM source uses "tenant_id" as the name of the currency value source
           .type(SourceColumn.TypeEnum.FQM))
       ));
@@ -431,7 +431,7 @@ void shouldIncludeCentralTenantIdInResponseForSimpleInstanceEntityType() {
       .name("tenant-id-test")
       .columns(List.of(new EntityTypeColumn()
         .name(valueColumnName)
-        .source(new SourceColumn(entityTypeId.toString(), valueColumnName)
+        .source(new SourceColumn(entityTypeId, valueColumnName)
           .name("tenant_id")  // The special FQM source uses "tenant_id" as the name of the currency value source
           .type(SourceColumn.TypeEnum.FQM))
       ));