|    Trav    |   Group    |   Subgroup   | Sheet_num  | T_val  |
|  SAT123A01 |   SAT123   |      A       |     1      |   400  |
|  SAT123A02 |   SAT123   |      A       |     2      |   0    |
|  SAT123A03 |   SAT123   |      A       |     3      |   0    |
|  SAT123A04 |   SAT123   |      A       |     4      |   0    |
|  SAT123A05 |   SAT123   |      A       |     5      |   500  |
|  SAT123B05 |   SAT123   |      B       |     5      |   400  |
|  SAT123B04 |   SAT123   |      B       |     4      |   0    |
|  SAT123B03 |   SAT123   |      B       |     3      |   0    |
|  SAT123B02 |   SAT123   |      B       |     2      |   500  |
|  SAT124A01 |   SAT124   |      A       |     1      |   400  |
|  SAT124A02 |   SAT124   |      A       |     2      |    0   |
|  SAT124A03 |   SAT124   |      A       |     3      |    0   |
|  SAT124A04 |   SAT124   |      A       |     4      |   475  |

new_t_val = delta / (cnt -1) * sheet_num + min_tvc_of_subgroup

|    Trav    |   Group    |   Subgroup   | Sheet_num  | T_val  |
|  SAT123A01 |   SAT123   |      A       |     1      |   400  |
|  SAT123A02 |   SAT123   |      A       |     2      |   425  |
|  SAT123A03 |   SAT123   |      A       |     3      |   450  |
|  SAT123A04 |   SAT123   |      A       |     4      |   475  |
|  SAT123A05 |   SAT123   |      A       |     5      |   500  |