Much more than drivers involved in using two different devices. The sample rates of each device have to be identical which requires synchronising of the 2 devices. Either by dedicated Clock inputs and outputs or at a pinch you can get away with using SPDIF connections. Failure to provide synch means that the clock from each device can drift from the other. When you think that the most basic and common sample rate is 44,100 samples per second you can see that it doesn't take much for two independent clocks to drift apart. This creates all sorts of horrible garbled unmusical sounds.

That's a very basic coverage of the topic.

BTW. Usually when requiring extra inputs you get a device from the same manufacturer where the ASIO driver is designed to see all the devices. In this case the driver is written with this purpose in mind.

Might I ask a question concerning your screen shot? Was, or were...all those tracks recorded from the same source material? I see the head of some tracks look identical while others appear a bit different. I'm assuming you didn't record all tracks at the exact same time,or did you?
Sorry, call me stupid...
I know what I'm looking at are the different latency values of a given track...I don't know, perhaps I'm not understanding latency quite as much as I probably should, but what seems to me is...any latency is bad, no matter how minimal.
Please...bust my chops where you will, but...
If track one starts on dead zero, then every overdub/added track afterward will have 'some' latency.
Then I might assume that all my tracks will look like your representation, except for the fact that all tracks recorded after the initial one will be 'dead on' to each other more than they would be to track 1.
Then, instead of nudging all the added tracks to track 1, would you move track one to match tracks 2~.
I've read a lot about...''x' much latency is acceptable'.
Is it?
so given even the acceptable amount, still, is it true, if you zoom in enough on even the lowest latency, you'll find it still looks like your screenshot?

Sorry if my question hijacked this thread