Not sure if you’re aware, I certainly wasn’t, but there are two types of battery charging hub available for the Mavic Pro.
The Flymore Combo ships with the ‘standard’ charging hub that intelligently works out which order it should charge the batteries in, but you can also get an ‘advanced’ charging hub.
On the outside, they look almost identical. The only real visible difference is the ‘advanced’ has a cooling fan built in and you can hear it, along with the holes being drilled out for the fan air flow.
On the underside, the charger connector is slightly different as the Standard hub will only accept the 50w Mavic mains charger, where the Advanced will accept the Mavic mains charger, the 12v car charger and also the 100w Phantom 4 charger.
If you’re using the 100w Phantom charger with the Advanced hub, you’ll also have the added advantage of it being able to charge three batteries simultaneously