A manufacturing company has four types of cost (identified as T1, T2 , T3 and T4).
The total cost for each type at two different production levels is:
 
Cost type       Total cost for 125 units      Total cost for 180 units
                                    
T1                         1,000                                   1,260
T2                         1,750                                   2,520
T3                         2,475                                   2,826
T4                         3,225                                   4,644
Which two cost types would be classified as being semi-variable?