Half a year in queue, awaiting full review - is it OK?

Hi! My queue number was 20 just yesterday - now it’s 22. It happens several times a week for last month - why? I see no progress for a long time. It’s suspicious: do some VIPs appear there, who need to be reviewed before others all the time?
Add-on link:
https://addons.mozilla.org/en-US/firefox/addon/cctoo/

No. One possibly scenario is that we have to put already reviewed versions back into the queue because we need to have another look at them.