I've seena number of ADRs recently that got their PPR with a day or 2 from submission of the Requested document(s). So this assertion isn't wholly true.
I would like to mention a few important details For anyone reading this:
PPR - May 21,2019
1. Do not hesitate to upload any additional document that you think will support your primary document asked. Make it into a single PDF and upload.
For example: If you are asked for proof of employment, do not just upload the letter of employment.
Also include: pay stubs at least for the last 3 months, bank statements.
When asked for a degree upload each and everything related to the educational degree.
When they ask for PCC also provide them the RCMP Fingerprint PCC don't wait for them to ask you biometric (keep it ready before applying to save time instead of dying from the inside waiting for PR)
2. The more details you add to your application the less it is likely to be asked for an ADR.
3. ADR delays the process by at least a month could even go to about 2 months. The process may complete within 6 months but who would want to wait until the last minute.
4. Please tell your Friends and Family who are applying for PR in CEC.
NOTE: IRCC will not reject your application for uploading too many supporting documents. They're there to help us get our permanent residence. Mostly the delay is from what we have given them as proof and how clear the application was to process.
Hope I was clear enough in saying and again "Supporting documents are a fastest way for PR"
There is nothing like "too much proof.".
Good luck to who ever is waiting on their PR/PPR.