Ok, mystery solved! First the good news: Someone did get back to me from Ipsos's standard email address. Kudos to them, though they did not use their name. The bad news is, they stated that Ipsos recently changed the compensation on Electronic Mystery Shops, at least. For closed locations the rate has been reduced from from $5 to $1. If the shopper waits 20 minutes and leaves without being served per the guidelines, the fee has been reduced from full fee to $5. They did not say if these fee reductions apply to other types of shops. They were not specific about when this change occured, other than "a short while back".
To get the full shop fee, shoppers must wait to be helped and have a full interaction. Hope that helps someone else who may have run into this, as well.