I just had an expensive toilet job: replaced flush and water valves in toilet tank. Because bowl was leaking onto floor, plumber replaced rotten wax ring under bowl. When he flushed the drain pipe or lead bend pipe, he said that it must be replaced due to back pitch and cracked flange. He said that the sign that it was cracked was because when he flushed the water down the floor pipe, water was still remaining in the pipe, which indicated that that pipe, which leads to the sewer was cracked, and would eventually leak down into the ceiling of the floor below me. Could this be true? And to make matters worse, he said that the job would cost $900. Thanks for your help.