I've had the same experience. If a tomato plant is tall and lanky, I just lay the entire stem over and cover it with soil. It roots all along that stem and the resulting plant is stocky and vigorous. No need to cut the plant off or even bury it deeply. I've even buried them sideways out of the pot, covered with soil and just left a few inches of the leafy end of the plant uncovered to grow upward. Works fine for me.
