It should work successfully. If it doesn't, then compare what you have to this, which does work:
var t_c = TempoClock.default;
{
var frequency1 = 200 + 600.rand;
var frequency2 = 200 + 600.rand;
var frequency3 = 200 + 600.rand;
var frequency4 = 200 + 600.rand;
var frequency5 = 200 + 600.rand;
var frequency6 = 200 + 600.rand;
var frequency7 = 200 + 600.rand;
var frequency8 = 200 + 600.rand;
var frequency9 = 200 + 600.rand;
var frequency0 = 200 + 600.rand;
var sinosc1 = { [ SinOsc.ar( freq:frequency1, mul:0.01 ), SinOsc.ar( freq:frequency1, mul:0.01 ) ] };
var sinosc2 = { [ SinOsc.ar( freq:frequency2, mul:0.01 ), SinOsc.ar( freq:frequency2, mul:0.01 ) ] };
var sinosc3 = { [ SinOsc.ar( freq:frequency3, mul:0.01 ), SinOsc.ar( freq:frequency3, mul:0.01 ) ] };
var sinosc4 = { [ SinOsc.ar( freq:frequency4, mul:0.01 ), SinOsc.ar( freq:frequency4, mul:0.01 ) ] };
var sinosc5 = { [ SinOsc.ar( freq:frequency5, mul:0.01 ), SinOsc.ar( freq:frequency5, mul:0.01 ) ] };
var sinosc6 = { [ SinOsc.ar( freq:frequency6, mul:0.01 ), SinOsc.ar( freq:frequency6, mul:0.01 ) ] };
var sinosc7 = { [ SinOsc.ar( freq:frequency7, mul:0.01 ), SinOsc.ar( freq:frequency7, mul:0.01 ) ] };
var sinosc8 = { [ SinOsc.ar( freq:frequency8, mul:0.01 ), SinOsc.ar( freq:frequency8, mul:0.01 ) ] };
var sinosc9 = { [ SinOsc.ar( freq:frequency9, mul:0.01 ), SinOsc.ar( freq:frequency9, mul:0.01 ) ] };
var sinosc0 = { [ SinOsc.ar( freq:frequency0, mul:0.01 ), SinOsc.ar( freq:frequency0, mul:0.01 ) ] };
var so1, so2, so3, so4, so5, so6, so7, so8, so9, so0;
t_c.sched( 1, { so1 = sinosc1.play; } );
t_c.sched( 6, { so2 = sinosc2.play; } );
t_c.sched( 11, { so3 = sinosc3.play; } );
t_c.sched( 16, { so4 = sinosc4.play; } );
t_c.sched( 21, { so5 = sinosc5.play; } );
t_c.sched( 26, { so6 = sinosc6.play; } );
t_c.sched( 31, { so7 = sinosc7.play; } );
t_c.sched( 36, { so8 = sinosc8.play; } );
t_c.sched( 41, { so9 = sinosc9.play; } );
t_c.sched( 46, { so0 = sinosc0.play; } );
t_c.sched( 51, { so1.free; } );
t_c.sched( 51, { so2.free; } );
t_c.sched( 51, { so3.free; } );
t_c.sched( 51, { so4.free; } );
t_c.sched( 51, { so5.free; } );
t_c.sched( 51, { so6.free; } );
t_c.sched( 51, { so7.free; } );
t_c.sched( 51, { so8.free; } );
t_c.sched( 51, { so9.free; } );
t_c.sched( 51, { so0.free; } );
}.value;