In April 2016 Mturk added a new "feature" now referred to as Throttling. What happens is when too many HITs have been accepted out of the same batch, Mturk will prevent additional workers from accepting more until the currently accepted HITs are submitted, returned or expired. A recent change (2017) to how throttling works now makes it so you can no longer preview a batch that is being throttled. This change means using a PanthA to try and get around throttling no longer works, rendering it useless and a waste of page requests. Example: Lets say that the limit to accepted HITs out of a single batch is 100. Customer Interest throttle doesn't seem bad because of the shorter completion times and short timer. This means HITs have a quick turnover rate allowing workers to more frequent accept work from the batch.. PicsFromAbove throttle seems bad because of the longer completion times and long timer. This means HITs idle in a workers queue a long time preventing other workers from being able to accept work from the batch. Disclaimer: This has not been confirmed by Mturk so technically it is speculation. That being said, I am confident in the above statements.