Yes, this is bugging me for a long time now, too. Thanks for posting this
A mineral extractor should be harvestable every 5 ticks or we should change the documentation to 6 seconds. One could argue that harvesting every 6 ticks in valid with a 5 tick cooldown. But labs, for example, can react every 10 ticks for a 10 tick cooldown reaction.
Consistency in any way would be fine, really.