+my @components = ( 'SRU' );
+# split/omit components as appropriate
+if ( $use_setup == 1 ) {
+ @components = ( 'S', 'RU' );
+}
+elsif ( $use_setup == 2 ) {
+ @components = ( 'RU' );
+}
+if ( $use_usage == 1 ) {
+ $components[-1] =~ s/U//; push @components, 'U';
+}
+elsif ( $use_usage == 2 ) {
+ $components[-1] =~ s/U//;
+}
+