Energy harvesting is a promising solution to the problem of limited battery life for wireless nodes. In this letter, the energy status during each round of transmission is analyzed, where the wireless node harvests energy from other co-channel transmitting nodes. Assuming round-robin scheduling, the probability mass function of the number of extra rounds offered by co-channel harvesting is calculated. Numerical results shows how the probability of extra transmissions changes with the amount of initial energy at each node and the number of nodes in the wireless network. They also show that the network where nodes are uniformly distributed over a line has a larger probability of extra transmissions than those uniformly distributed over a disc or equally spaced over a line.