diff --git a/v2.3/toolkit/src/fnlo-tk-rootout.cc b/v2.3/toolkit/src/fnlo-tk-rootout.cc
index 8c7a8f7dfe4568c064f86f5cdec86ba43fe60b41..f74747f8a305f68ac20d3c28ae3d5b398c39417c 100644
--- a/v2.3/toolkit/src/fnlo-tk-rootout.cc
+++ b/v2.3/toolkit/src/fnlo-tk-rootout.cc
@@ -116,8 +116,9 @@ int main(int argc, char** argv) {
          man << "   Default:      \"kScale1\",  i.e. mur=muf=scale1," << endl;
          man << "   Alternatives: \"kScale2\",  i.e. mur=muf=scale2," << endl;
          man << "                 \"scale12\", i.e. mur=scale1, muf=scale2," << endl;
-         man << "                 \"scale21\", i.e. mur=scale2, muf=scale1." << endl;
-         man << "                 \"kProd\", i.e. mur=muf=scale1*scale2." << endl;
+         man << "                 \"scale21\", i.e. mur=scale2, muf=scale1," << endl;
+         man << "                 \"kProd\", i.e. mur=muf=scale1*scale2," << endl;
+         man << "                 \"kQuadraticSum\", i.e. mur=muf=sqrt(scale1^2+scale2^2)." << endl;
          yell << " #" << endl;
          man << "Use \"_\" to skip changing a default argument." << endl;
          yell << " #" << endl;
@@ -365,6 +366,9 @@ int main(int argc, char** argv) {
       } else if ( chflex == "kProd" ) {
          fnlo->SetMuFFunctionalForm(kProd);
          fnlo->SetMuRFunctionalForm(kProd);
+      } else if ( chflex == "kQuadraticSum" ) {
+         fnlo->SetMuFFunctionalForm(kQuadraticSum);
+         fnlo->SetMuRFunctionalForm(kQuadraticSum);
       } else {
          error["fnlo-tk-rootout"] << "Unknown scale choice " << chflex << ", aborted!" << endl;
       }
diff --git a/v2.3/toolkit/src/fnlo-tk-yodaout.cc b/v2.3/toolkit/src/fnlo-tk-yodaout.cc
index d80c0a852c5f37ba8d855b707283820a4547d8e2..e0a6399aef46dfdbe29def8bc0c6eec3d30c825d 100644
--- a/v2.3/toolkit/src/fnlo-tk-yodaout.cc
+++ b/v2.3/toolkit/src/fnlo-tk-yodaout.cc
@@ -119,8 +119,9 @@ int main(int argc, char** argv) {
          man << "   Default:      \"kScale1\",  i.e. mur=muf=scale1," << endl;
          man << "   Alternatives: \"kScale2\",  i.e. mur=muf=scale2," << endl;
          man << "                 \"scale12\", i.e. mur=scale1, muf=scale2," << endl;
-         man << "                 \"scale21\", i.e. mur=scale2, muf=scale1." << endl;
-         man << "                 \"kProd\", i.e. mur=muf=scale1*scale2." << endl;
+         man << "                 \"scale21\", i.e. mur=scale2, muf=scale1," << endl;
+         man << "                 \"kProd\", i.e. mur=muf=scale1*scale2," << endl;
+         man << "                 \"kQuadraticSum\", i.e. mur=muf=sqrt(scale1^2+scale2^2)." << endl;
          man << "[np]: Apply nonperturbative corrections if available, def. = no." << endl;
          man << "   Alternatives: \"yes\" or \"np\"" << endl;
          yell << " #" << endl;
@@ -399,6 +400,9 @@ int main(int argc, char** argv) {
       } else if ( chflex == "kProd" ) {
          fnlo->SetMuFFunctionalForm(kProd);
          fnlo->SetMuRFunctionalForm(kProd);
+      } else if ( chflex == "kQuadraticSum" ) {
+         fnlo->SetMuFFunctionalForm(kQuadraticSum);
+         fnlo->SetMuRFunctionalForm(kQuadraticSum);
       } else {
          error["fnlo-tk-yodaout"] << "Unknown scale choice " << chflex << ", aborted!" << endl;
       }