A downhole tool can perform a series of operations with balls of the same size where movement caused by pressuring up on the first ball positions the next seat to accept another ball just like it. In a preferred embodiment a circulation sub is run in with a port closed and a first seat comprising of collets pushed together and preferably lined with a sleeve are in position to accept a first ball to perform a downhole operation and thereafter pass the ball and open the port. The act of opening the port gives support, by reducing their dimension, to the next assembly of collets also preferably lined with a sleeve so that they are energized to accept the same size ball. Pressuring up on the second ball can shift another sleeve to close the circulation port. The tool is modular and more than one module can be deployed in a given bottom hole assembly.