OLYMPIC does use what are called continuation matchups, typically. They are for the whole tournament no matter when they are offered. So they sometimes include one or two stroke disparities when you make them, sometimes more or "stroke lines" are thrown in. That is why the lines are sometimes lopsided.
They did offer single round betting for the Masters this year, the first time I can ever remember seeing them there. They clearly differentiated them from the continuations.
They do sometimes have decent value, but the 30 cent lines/spread is a factor to consider.
GL