This can cause problems, if you have the a PPOS followed by the final fix for the runway, if you delete the PPOS then the flightplan will sequence to the runway threshold. That is fine unless you then are vectored past the runway threshold within 7nm. If this happens then you will potentially lose the entire flight plan as the FMGC thenks you have landed.
At my previous airline it was policy not to delete the PPOS until you were on the final intercept. At my current airline when flying a visual circuit you don't take the PPOS out at all due to the above problem.