This is my new rule of thumb when it comes to cross-complaints filed after the answer: if you are late in filing your cross-complaint and need to seek leave of the court to file it, for frak's sake, do everything you can to characterize it as a compulsory and not permissive.
Yes, this is wonky type thing to say. No, do not take this as actual, legal advise because unless you are one of a very small number of people who are actually my clients. I do not know if this advise is even applicable to you and your situation. It is merely for information only as I sit here, pulling my hair out while I try and stitch together an appeal for he who is my, as Rumpole would say, learned leader.