Correct computer power supply for different devices (W, V, A)?

For a docking station, I would like to buy a power adapter to charge my laptop and not have to look for power adapters every time. However, I currently use two computers (private and professional) with the following data from the power supply units:

Private: 85W and 20V (MacBook Pro 15 ", mid 2014)

Company: 65W and 19.5V (Dell Latitude 7480)

As soon as the new MacBooks are out, my personal computer will be replaced, which makes it even more complicated. The power supplies of the current line-up and, hopefully, similarly those of the next devices, have the following data:

60W and 20.3V
96W and 20.5V

I've already read that the W don't care. So they can be higher because the devices only "take" what they need.

But what about the different tensions? Buy a power supply with max. 19.5V, as this is the lowest voltage of all devices? The difference between the other power supplies is not that great… They won't charge that much slower then?!

What are you messing about about 0.2 volts that is, according to my calculation, about 0.1% you can hardly measure that, if the plugs fit it doesn't matter and the power packs have a much greater tolerance than 0.1% .

I would take 20 V, the maximum error is 0.5V. Should all computers survive.