Yeah, the ‘maximum range’ part of the orders is a bit confusing. It actually means ‘get at least this close to the opposition’. So a ‘max’ of 2000, means your ships won’t approach past 2000. Keep moving means your ships will get a bit closer/bit further away, but they’ll still try to stay at least half the max range away - 1000 in this case, which is further than any weapon can shoot except missiles.
Usually, you want to set your range order to about 100 less than your main weapons.
With keep moving, you can get away with setting your orders a little over that, if you want to keep the enemy at arms length, since they’ll get a bit closer in their milling around.
Not sure what you meant by giving formation and keep moving, since as far as I know you’re still only able to have one of those enabled at once (but we have been asking rather persistently to be able to have them both (just with formation taking precedence until the formation target dies.)