From what I have seen, most of the PEBLOs who give approximate timelines are inaccurate. Either they just straight up do not know and they are only going on gouge, or they are giving an estimate based on previous experience or trends. Therefore, if the timeline is getting shorter for any step in the process, they don't reflect that with their estimate because their most recent experience was longer. Case in point, a year ago the average time in DES for Navy was about 425 days. Snapshot this past july, the average time was $322 days or something like that. About 100 days cut off. But people were still being told it was going to take them to longer period of time, because the newest information wasn't out there at the Peblo level.
Historically the time in the QA process has ranged between two and six weeks. However, that time has been dropping recently, and people have been spending as little as a week in that step. So if you have already talked to someone at PEB and they have told you a shorter time then what your Peblo has said, I would believe the staff member first.
All of that is with the caveat that every case is different, and depending on what they find in the process, or how complex your individual cases, you could be a statistical outlier and take longer.