Should the USB MIDI connection be made directly for less latency?
Back in the days where we had HUB's in computer networks, these things slowed the data flow down drastically. A HUB is directing only one data packet at a time, so if two ports are sending data, the HUB can redirect some data packets from one port, then from the second, back to the first one, and so on...
What I've learned from the guys here is that also USB isn't working in duplex (read and write at the same time), but as a serial device (read then write and vise verse); meaning that if you also have other periferials connected to your HUB (like an external hard drive), data going to these can hinder the data your MIDI controller is trying to send.
But of course the best way to find out what is causing the problem, is plugging your controller directly into your USB-port. If this works fine, then you try it alone through your HUB. If this again works fine, start pluging one item at a time into the HUB, seeing if any of these introduce the latency problem in Logic.