Transfer function identification procedure?

I tried the following

s=tf('s');
sys=(s+2)/((s+3)*(s+10)); 
t=1:.5:50;
in_data_gen=rand(99);
in_put=in_data_gen(:,1)
[y tt]=lsim(sys,in_put,t);
-----

then i exported "in_put" and "y" to system identification tool box. and tried to estimate with 2 pole and 1 zero option . but i got TF

   0.5 (s+1)
  -------------
  (s+5) (s+1.5)

which is not matching the input tf.. I dont know why ? can u suggest