The Carib half point is actually more like a free 1/4th point because you don't get a half point on either side. With Skybook, if the "normal" line is +8, you get +8.5 or -7.5. With Carib, if the "normal" line would be +8, they'd either be offering +8.5 and -8 or +8 and -7.5. Carib, however, offers the free 1/4th point around the 3 and 7, which Skybook does not.