Strange, i've bought DCs pretty much exclusively the last few years and find them very consistent in the sizing as far as length goes, but they deffo vary on the width from shoe to shoe.
I'm a 10.5 and would say that DC run TTS... the one exception would be the DC Maswell maybe feels like a quarter size bigger, but not enough for me to come down to a 10...main reason for that is the Maswell run pretty wide in the forefoot, I can actually feel the whole of the front of my foot slide sideways in them sometimes.
I haven't had a pair come up too small or big and i've had multiple pairs of Tiago S, Penza, Maswell, Legacy slim, Williams slim recently, actually got a pair of Penza, Maswell and Legacy slim under my desk as I type this lol.
In length I'm the same size across DC, Globe, Circa (RIP), Etnies, Adidas, Osiris. I'm not sure if DC sizing may vary a bit between vulc and cupsole, I only skate cupsoles so can't really compare.