diff --git a/apsuite/loco/config.py b/apsuite/loco/config.py
index 21bf77cfe..d58ed6c1f 100644
--- a/apsuite/loco/config.py
+++ b/apsuite/loco/config.py
@@ -459,6 +459,12 @@ def update_weight(self):
 
     def update_quad_knobs(self, use_families):
         """."""
+        if self.quadrupoles_to_fit == []:
+            # empty list does not update knobs
+            # knobs must be set directly to the
+            # quad_indices_kl attribute
+            self.quad_indices_ksl = self.quad_indices_kl
+            return
         if self.quadrupoles_to_fit is None:
             self.quadrupoles_to_fit = self.famname_quadset
         else:
@@ -514,22 +520,35 @@ def update_sext_knobs(self, use_families):
 
     def update_skew_quad_knobs(self):
         """."""
-        if self.skew_quadrupoles_to_fit is None:
-            self.skew_quad_indices_ksl = self.respm.fam_data['QS']['index']
-        else:
+        if self.skew_quadrupoles_to_fit == []:
+            # empty list does not update knobs
+            # knobs must be set directly to the
+            # quad_indices_kl attribute
+            return
+        if self.skew_quadrupoles_to_fit is not None:
             skewquadfit = set(self.skew_quadrupoles_to_fit)
             skewquadall = set(self.famname_skewquadset)
+            skewquadall = skewquadall.union(set(self.famname_idskewquadset))
             if not skewquadfit.issubset(skewquadall):
                 raise Exception('invalid skew quadrupole name used to fit!')
-            else:
-                self.skew_quad_indices_ksl = []
-                for fam_name in self.skew_quadrupoles_to_fit:
-                    fam = self.respm.fam_data
-                    self.skew_quad_indices_ksl += fam[fam_name]['index']
-                idx_all = _np.array(self.respm.fam_data['QS']['index']).ravel()
-                idx_sub = _np.array(self.skew_quad_indices_ksl).ravel()
-                self.skew_quad_indices_ksl = list(set(idx_sub) & set(idx_all))
-                self.skew_quad_indices_ksl.sort()
+
+            self.skew_quad_indices_ksl = []
+            for fam_name in self.skew_quadrupoles_to_fit:
+                fam = self.respm.fam_data
+                self.skew_quad_indices_ksl += fam[fam_name]['index']
+            idx_all = _np.array(self.respm.fam_data['QS']['index']).ravel()
+            idx_all = _np.concatenate((
+                idx_all,
+                _np.array(self.respm.fam_data['IDQS']['index']).ravel(),
+            ))
+            idx_sub = _np.array(self.skew_quad_indices_ksl).ravel()
+            self.skew_quad_indices_ksl = list(set(idx_sub) & set(idx_all))
+            self.skew_quad_indices_ksl.sort()
+            self.skew_quad_indices_ksl = [
+                [idx] for idx in self.skew_quad_indices_ksl
+            ]
+            return
+        self.skew_quad_indices_ksl = self.respm.fam_data['QS']['index']
 
     def update_b1_knobs(self):
         """."""
@@ -727,6 +746,11 @@ def famname_skewquadset(self):
             'SDP3',
         ]
 
+    @property
+    def famname_idskewquadset(self):
+        """."""
+        return ['IDQS']
+
 
 class LOCOConfigBO(LOCOConfig):
     """Sirius Booster LOCO configuration."""
diff --git a/apsuite/loco/main.py b/apsuite/loco/main.py
index 20b6319a9..31042989e 100644
--- a/apsuite/loco/main.py
+++ b/apsuite/loco/main.py
@@ -479,14 +479,25 @@ def save_jacobian(self):
             _LOCOUtils.save_data('6d_KL_sextupoles', jloco_kl_sext)
 
         if self.config.fit_skew_quadrupoles:
-            idx_qs = self.config.respm.fam_data['QS']['index']
-            sub_qs = self.config.respm.fam_data['QS']['subsection']
+            idx_qs_all = self.config.respm.fam_data['QS']['index']
+            idx_qs_all += self.config.respm.fam_data['IDQS']['index']
+            sub_qs_all = self.config.respm.fam_data['QS']['subsection']
+            sub_qs_all += self.config.respm.fam_data['IDQS']['subsection']
             idx_qs = self.config.skew_quad_indices_ksl
-            selidx = []
-            for sel in self.config.skew_quad_indices_ksl:
-                selidx.append(idx_qs.index([sel]))
-            idx_qs = [idx_qs[idx] for idx in selidx]
-            sub_qs = [sub_qs[idx] for idx in selidx]
+
+            idx_flat, sub_flat = [], []
+            for idxs, sub in zip(idx_qs_all, sub_qs_all):
+                if isinstance(idxs, list):
+                    idx_flat.extend(idxs)
+                    sub_flat.extend([sub] * len(idxs))
+                else:
+                    idx_flat.append(idxs)
+                    sub_flat.append(sub)
+
+            sub_qs = []
+            for i in idx_qs:
+                sub_qs.append(sub_flat[idx_flat.index(i[0])])
+
             jloco_ksl_skewquad = self.create_new_jacobian_dict(
                 self._jloco_ksl_skew_quad, idx_qs, sub_qs
             )
@@ -946,6 +957,7 @@ def _create_output_vars(self):
             self._girders_shift_inival + self._girders_shift_deltas
         )
         self.kldelta_history = self._kldelta_history
+        self.ksldelta_history = self._ksldelta_history
 
     def clear_output_vars(self):
         """."""