Dear Amir,
I have no doubt in first three cases, but If we change some points in case 4 and 5, than what will be the answer-
1.If the date of payment in case no. 4 for all the contract are differents, and every contract were totaly seprate contract with each other but contractor were same.wt will be the answer.whether TDS is applicable since first contract payment or at the time of contract C, at this time limt 0f Rs.50000/- is applied.
2.if in Case 5, We change the amount of Contract B with Rs.10000/- in lieu of Rs.19000/-, than what will be the answer.whether still TDS is to be deducted on both contracts..?