I disagree with the wording that is talked about. The description does not define a multi tiered cast, it only describes one cast from your original body to a jar, and then a host.
Due to this, it wouldn't make sense to word it in any other way than how they did it. They differentiate between the host body and your body in order to clarify the spell, but since they do not mention multiple casts, it would be safe to assume that "your body" is referring to the body that you are casting from, and therefore it would daisy chain the effect.
If a spell is cast from your body, it is cast from the body that you are in control of, so if you cast magic jar from a host body, and destroy the first host body, then your soul would not have to attempt to leave, the soul in the first jar would die, and your original body would be in a catatonic state.
But if the second jar were to then be destroyed, your soul would have no body to go into, since the first host body was killed. However, you would be able to transfer to the jar, and then to your original body, but the jar would still need to remain intact.
Essentially, you would create steps of the spell that you would need to backtrack through in order to safely end the spell completely. Otherwise, there will always be a chance of death from being dispelled, or the jar breaking and not being able to go back one step.