JEFE--thanks for bringing this topic to discussion. First, I was not aware of the difference in wheels. I searched for some information about the meaning of HUB-CENTRIC versus LUG-CENTRIC. I found several good resources that explained the difference. Here is a good resource with illustrations:http://www.machinedesign.com/fasteners/what-s-difference-between-lug-centric-and-hub-centric-wheels
In wheels that are made as HUB-CENTRIC the wheel fits snugly against the hub which provides support along with the hub's lugs. There is no gap between the hub and the wheel. Wheels of this type are used by automobile OEM's because the support and centering of the wheel on the hub is better; the wheel resists impact loads encountered on typical roads. Also, the exact center of the wheel is the center of the hub.
In wheels that are made as LUG-CENTRIC the wheel does not fit snugly against the hub; there is a gap between wheel and hub. Wheels like this are made for aftermarket applications because they will fit on a wider variety of hubs. The drawback to the lug-centric wheel is the reduced support from the lack of firm fit to the hub. The lug bolts carry all the loading. Lug-centric wheels are often used on low-speed vehicles like golf carts. Also, the exact center of the wheel is the center of the bolt-circle of the lug holes, and may not be precisely coincident the center of the hub.
I have heard a old wive's tale: do not get trailer tires balanced. I never heard any reason behind this. I can understand this old rule better now. I presume that most tire stores would balance a wheel with the expectation that the wheel is a hub-centric design. The wheel is usually fitted to the balancer with a temporary mount that does not use the lug bolt holes as a means of fastening the wheel. If a lug-centric wheel is balanced by using the hub of that wheel as the precise center, there could be a difference in the location of the actual center of the lug-hole bolt-circle and the hub hole. This could result in an improper balance.
Also interesting to note: this difference reveals the use of lug-bolts instead of lug-nuts on many trailer wheels. On my E-Z-LOADER trailer, the hubs do not have studs; the hubs have threaded holes. The wheel is fastened by five lug-bolts, and the bolts have a tapered shaft. The tapered shafts of the lug-bolts helps to center the lug-holes in the wheel over bolt-holes on the hub. Also, a lug-nut usually has a tapered face on one side to help accomplish the same centering on the hub studs.