diff --git a/lib_com/options.h b/lib_com/options.h
index fca9b4b0f646c849ef65c960f065f9722b2511ae..e506d6b6524af5a40b242503b56345252da57191 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -102,6 +102,7 @@
 #define FIX_FLOAT_1600_OMASA_WRONG_RENDER_PATH          /* Nokia: float issue 1600: fix initialization condition of stereo type detection for OMASA */
 #define FIX_BASOP_1765_MASA1TC_CNG_MISMATCH             /* Nokia: BASOP issue 1765: Improve accuracy of FD CNG noise estimation */
 #define FIX_BASOP_2627_PARAM_MC_ILD_REMAP_EXP           /* FhG: BASOP #2627: accumulate 10^(ILD/10) using a dynamic exponent */
+#define FIX_BASOP_2635_EFAP_ADD_VERTEX_ELE_ROUND        /* FhG: BASOP #2635: round |elevation| with anint_fx before the 90deg subtraction in add_vertex_fx */
 
 /* ##################### End NON-BE switches ########################### */
 
diff --git a/lib_rend/ivas_efap_fx.c b/lib_rend/ivas_efap_fx.c
index 9a3cb2f0b05e78b98b48e99780757382a8bf6d8b..d716c5b7d656cd1bbb071c77bc6fa95f15e974df 100644
--- a/lib_rend/ivas_efap_fx.c
+++ b/lib_rend/ivas_efap_fx.c
@@ -1696,8 +1696,13 @@ static void add_vertex_fx(
 
     /* IdxEleTmp */
     tmp = L_abs( vtxArray[pos].ele ); // q22
-    idxEleTmp = tmp;                  // q22
+#ifdef FIX_BASOP_2635_EFAP_ADD_VERTEX_ELE_ROUND
+    idxEleTmp = anint_fx( tmp, Q22 ); // q22
+    move32();
+#else
+    idxEleTmp = tmp; // q22
     move16();
+#endif
     idxEleTmp = L_sub( Q22_90_DEG /*90 q22*/, idxEleTmp ); // q22
 
     /* Final Idx */