diff --git a/src/index.ts b/src/index.ts
index df0252d..43a3dd7 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -240,7 +240,7 @@ app.get('/api/trigger-product-structures-sync', (req: Request, res: Response) =>
     options: {
       skus: env.PRODUCT_STRUCTURE_SKUS || null,
       productIds: env.PRODUCT_STRUCTURE_PRODUCT_IDS || null,
-      inputFile: env.PRODUCT_STRUCTURES_INPUT_FILE || '/app/data/product-structure-products.csv',
+      inputFile: env.PRODUCT_STRUCTURES_INPUT_FILE || ((env.PRODUCT_STRUCTURE_SKUS || env.PRODUCT_STRUCTURE_PRODUCT_IDS) ? null : '/app/data/product-structure-products.csv'),
       graphsUrl: env.PRODUCT_STRUCTURES_GRAPHS_API_URL || env.PRODUCTION_ORDERS_GRAPHS_API_URL || env.GRAPHS_PRODUCTION_ORDERS_API_URL || deriveProductionOrdersUrl(env),
       dryRun: env.PRODUCT_STRUCTURES_DRY_RUN || 'false',
       maxProducts: env.PRODUCT_STRUCTURES_MAX_PRODUCTS || null,
diff --git a/src/scripts/sync-product-structures.ts b/src/scripts/sync-product-structures.ts
index c4fd6ac..cc45d88 100644
--- a/src/scripts/sync-product-structures.ts
+++ b/src/scripts/sync-product-structures.ts
@@ -92,8 +92,6 @@ const GRAPHS_PRODUCTION_ORDERS_API_KEY = (
     process.env.API_KEY ||
     'nexstar_secret_key_123'
 );
-const DEFAULT_INPUT_FILE = path.join(process.cwd(), 'data', 'product-structure-products.csv');
-const INPUT_FILE = process.env.PRODUCT_STRUCTURES_INPUT_FILE || (fs.existsSync(DEFAULT_INPUT_FILE) ? DEFAULT_INPUT_FILE : '');
 const SKUS = String(process.env.PRODUCT_STRUCTURE_SKUS || '')
     .split(',')
     .map(value => value.trim())
@@ -102,6 +100,10 @@ const PRODUCT_IDS = String(process.env.PRODUCT_STRUCTURE_PRODUCT_IDS || '')
     .split(',')
     .map(value => value.trim())
     .filter(Boolean);
+const DEFAULT_INPUT_FILE = path.join(process.cwd(), 'data', 'product-structure-products.csv');
+const EXPLICIT_INPUT_FILE = process.env.PRODUCT_STRUCTURES_INPUT_FILE || '';
+const SHOULD_USE_DEFAULT_INPUT_FILE = !EXPLICIT_INPUT_FILE && !SKUS.length && !PRODUCT_IDS.length && fs.existsSync(DEFAULT_INPUT_FILE);
+const INPUT_FILE = EXPLICIT_INPUT_FILE || (SHOULD_USE_DEFAULT_INPUT_FILE ? DEFAULT_INPUT_FILE : '');
 const DRY_RUN = process.env.PRODUCT_STRUCTURES_DRY_RUN === 'true';
 const FETCH_COMPONENT_UNITS = process.env.PRODUCT_STRUCTURES_FETCH_COMPONENT_UNITS !== 'false';
 const STATE_FILE = process.env.PRODUCT_STRUCTURES_STATE_FILE || path.join(process.cwd(), 'product_structures_sync_state.json');