The math is simple:
– 3 ml units per month (30 days) production capacity;
– orders made on 15th of June are delivered on 25th of June; – orders made on 17th of June are delivered on 14th of July
Conclusion : Apple is about to reach full capacity for 20 days production time , therefore there are around 2 ml units sold or reserved.
Not to mention that for the startup they may have had ready a bit more than 3 mil units…