Surprisingly, this does seem to be the case, even when volume loads are greater with moderate load training. (strengthandconditioningresearch.com)
The most common training program is heavy loads for core lifts, and then moderate loads for isolation lifts. (gymjunkies.com)
They can enhance overall performance when done at moderate loading with the highest emphasis on movement integrity rather than heavier loading. (blog.trainheroic.com)