Again thanks a lot everybody.
Their favourite day is Friday - that is when lot of PPR does come.
My observations are following:
They seem to move applications from queue to queue.
That means:
1. First queue is for medicals (that one is done rather fast in most cases)
2. Queue for criminality check and also to start security checks - at this point you can get rejections for PPC or ADR for Schedule A or your detailed travelling history.
3. Queue for R10 - here you can get further rejections for missing documents. Once you pass this you will also get criminality confirmed.
4. A11.2 Queue - at this point rejections for wrong NOC, incorrect reference letters or too low POF can happen. This one is also pretty fast.
5. Queue for LVO tranfer - they transfer applications to LVO in batches (so maybe just 1x per week to your LVO)
6. Queue for second analyst confimation at LVO. Only done after all security checks are done as well.
7. Queue for release of PPR under your stream (FSW, CEC, PNP).
If they have ADR or they need deeper investigation your application will be postponed and waiting for that to be done before resuming and putting to the waiting queue again.
That is the reason for delays.