I wonder if they think they have 15 days (they would if they were filing a 10K or other documents). However they only have 5 calendar days for a 10Q.
The compilation, dissemination and review of the information required to be presented in the Form 10-Q for the relevant fiscal quarter has imposed time constraints that have rendered timely filing of the Form 10-Q impracticable without undue hardship and expense to the registrant. The registrant undertakes the responsibility to file such quarterly report no later than 5 days after its original due date.