I usually did the load shift from about 2pm until 9pm at night, and for a couple of weeks before I left, that was all I did. My hours went from 12-15 hours for training, to 20+ hours a week shortly after then dropped to 7 hours with no real reason as to why.
The load shift was the best part of that job, moving stock onto shelves and making them presentable was great as it was something to do for a while, sometimes the whole 7 hours was spent doing load, and I enjoyed that. But if I was there when load was done, my list was; do recovery, help customers and sometimes that's all I did for the whole day so it often became a drag.
Doing load or stock is fun.
Long patches of downtime.