I'm a little confused as to which is the one and which is the many form. I'd say the main form would be Clients and the sub ought to be Jobs but you have it the other way around. My logic is that each client (one at a time) could have several jobs identified with them, so if you have it backwards, that's not helping. Keeping with my logic, the other aspect to consider if that you want to create a new client, that has to happen first as you have discovered, which cannot happen if you put them on the subform.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.