supreme court in "Amardeep singh And Harveen kaur" ruled that :-
“we’re of the view that where the Court dealing with a matter is satisfied that a case is made out to waive the statutory period under Section 13B(2), it can do so after considering the following :-
i) the statutory period of 6 months specified in Section 13B(2), in addition to the statutory period of 1 year under Section 13B(1) of separation of parties is already over before the 1st motion itself;
ii) all efforts for mediation or conciliation including efforts in terms of Order XXXIIA Rule 3 CPC/Section 23(2) of the Act/Section 9 of the Family Courts Act to reunite the parties have failed & there’s absolutely no likelihood of success in that direction by any further efforts;
iii) the concerned parties have genuinely settled their differences including alimony, custody of child, any other pending issues between the parties;
iv) the waiting period’ll only prolong their agony.
The Supreme court said that the waiver application can be moved in court after one week of the first motion in the court , by citing the reasons of waiver.
The waiver is absolutely the discretion the Concerned Court
Supreme Court concluded that since the period mentioned in Section 13B(2) isn’t mandatory but directory, it’ll be open to the Court to exercise its discretion in the facts & circumstances of each case, where there’s no possibility of parties resuming cohabitation & there’re chances of alternative rehabilitation.
The ruling doesn't say it is mandatory in fact it was throwing lights on the existing provisions in a practical manner, hence it is not applicable and followed to every petition by mutual consent.
answering to your questions
1. The application can be filed one week after the first motion
2. The urgency or the circumstances requesting to waive off has to be mentioned in the Petition, it could be the reasons of existing disputes which were withdrawn after settling, long years of separation, any one of the spouse moving out of country for job, or any other genuine reasons which Court can be convinced the urgency.