The answer depends on the FC level itself since most of the chlorine is lost due to breakdown from sunlight so it's a FRACTION of the FC that gets broken down over time, not an absolute number. Losing around half of the FC level during the day seems to be typical on the high side. Some have reported maintaining high CYA levels and seeing far less usage.

So how much of the 5 ppm FC do you lose in a day with your 60 ppm CYA level? If it's more than 2.5 ppm FC, then you might have other consumption related to organics in the pool or nascent algae growth. Your chlorine consumption overnight when the sun isn't shining will give you some idea of this extra chlorine usage.

Richard