No, there is no maximum time. But clearly they are aware of the deadline and that is probably why they moved your interview forward. It is quite possible they did this with a number of other selectees too, so they may have a pile of such documents to get through. If it has been confirmed that they have the docs and are ready for review by the CO, you can’t really do anything else but wait at this stage. Look at it this way: on the original schedule, you’d still be nearly 2 weeks away from even being interviewed.