Can a leeter on non deduction will work for service tax

ONE OF MY CLIENT DEALS IN GTA INDUSTRIES THEY HAVE 4 GROUP COMPANIES AND THEY USALLY TAKE VEHICLES OF ONE COMPANY TO OTHER FOR FREIGHT PURPOSE AND GIVES SERVICE OF GTA TO THIRD PARTY AND THE COMPANY WHICH TAKES THE VEHICLE PAYS ALL THE SERVICE TAX LIABILITY ,THUS IN CASE WHEN THE COMPANY WHICH GIVES THE VEHICLE RECORD THE INCOME UNDER FREIGHT , SO MY QUESTION IS IF THE COMPANY WHICH TAKES THE VEHICLE GIVES A LETTER TO THE COMPANY WHICH GIVES VEHICLE THAT THEY SHOULD NOT ADD THE AMOUNT OF SERVICE TAX AS THEY ARE CHARGING AND SUBMITTING, WILL THE COMPANY HAVE ANY LIABILITY?(WHICH IS GIVING THE VEHICLE)