When your CO sent your case for 2pc, it joined the back of a date and time order queue from all the other COs who send to that office. Some time will be passing while it works its way to the front of the queue to get its turn for attention. When it gets its turn, the 2pc official will look over everything about the case - check that all the necessary evidence is there for what you claimed about yourself, and that your CO followed INZ procedure correctly. (If there's anything missing, or wrong, the case gets sent back to your CO, for him/her to correct things, or to require extra the evidence or explanations. This is quite rare.) The actual checking doesn't take very long; it's the queuing that can stretch out. There is no 'usual' time frame, because the length of the queue depends on how much work went through from the COs just before your case, and that is totally unpredictable.