diff --git a/wetb/dlc/high_level.py b/wetb/dlc/high_level.py
index 418de910337dafd4fb557fdb99e75e126d8b1f27..0edfa43b109cd4eba748e6ba881f2a663129a525 100644
--- a/wetb/dlc/high_level.py
+++ b/wetb/dlc/high_level.py
@@ -231,10 +231,11 @@ class DLCHighLevel(object):
         fatigue_dlcs = self.dlc_df[['F' in str(l).upper() for l in self.dlc_df['load']]]['dlc']
         if len(fatigue_dlcs) == 0:
             return {}
+        ext = getattr(self, 'res_ext', ".sel")
         if isinstance(files, list):
             pass
         elif not hasattr(self, "res_folder") or self.res_folder == "":
-            files = glob.glob(os.path.join(self.res_path, "*.sel")) + glob.glob(os.path.join(self.res_path, "*/*.sel"))
+            files = glob.glob(os.path.join(self.res_path, "*"+ext)) + glob.glob(os.path.join(self.res_path, "*/*"+ext))
         else:
             files = []
 
@@ -244,7 +245,7 @@ class DLCHighLevel(object):
                     folder = self.res_folder % dlc_id
                 else:
                     folder = self.res_folder
-                files.extend(glob.glob(os.path.join(self.res_path , folder, "*.sel")))
+                files.extend(glob.glob(os.path.join(self.res_path , folder, "*"+ext)))
         keys = list(zip(*self.dist_value_keys))[1]
         fmt = self.format_tag_value
         tags = [[fmt(tag.replace(key, "")) for tag, key in zip(os.path.basename(f).split("_"), keys)] for f in files]
diff --git a/wetb/dlc/tests/test_files/DLC_test_flex.xlsx b/wetb/dlc/tests/test_files/DLC_test_flex.xlsx
new file mode 100644
index 0000000000000000000000000000000000000000..cebcdd2ae3eeff59369e4a1950700f0679e3883a
Binary files /dev/null and b/wetb/dlc/tests/test_files/DLC_test_flex.xlsx differ
diff --git a/wetb/dlc/tests/test_files/res/dlc12_iec61400-1ed3/dlc12_wsp04_wdir350_s3001.int b/wetb/dlc/tests/test_files/res/dlc12_iec61400-1ed3/dlc12_wsp04_wdir350_s3001.int
new file mode 100644
index 0000000000000000000000000000000000000000..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
diff --git a/wetb/dlc/tests/test_high_level.py b/wetb/dlc/tests/test_high_level.py
index 473e81bd6d36eb1adc54304b2d75ede8b0413fdc..a8dbb08322765951ef46ebe87e438f3e56b8c42d 100644
--- a/wetb/dlc/tests/test_high_level.py
+++ b/wetb/dlc/tests/test_high_level.py
@@ -56,6 +56,11 @@ class TestDLCHighLevel(unittest.TestCase):
         self.assertEqual(os.path.abspath(f), os.path.abspath(testfilepath + 'res/dlc31_iec61400-1ed3/dlc31_wsp25_wdir000_s0000.sel'))
         self.assertAlmostEqual(h, 0.0087201928 * 1 * (50 / 1100) * 20 * 365 * 24)
 
+    def test_file_dict_flex(self):
+
+        dlc_hl = DLCHighLevel(testfilepath + 'DLC_test_flex.xlsx')
+        self.assertEqual(dlc_hl.files_dict()[12][4][350]['files'],  ['C:/mmpe/programming/python/WindEnergyToolbox/wetb/dlc/tests\\test_files\\res\\dlc12_iec61400-1ed3\\dlc12_wsp04_wdir350_s3001.int'])
+
 
     def test_dlc_lst(self):
         self.assertEqual(self.dlc_hl.dlc_lst(), ['12', '13', '14', '31'])