The RhinoCommon Patch stuff uses completely different code than the Patch command. But you should be able to produce surfaces that are nearly identical.
The function that takes no starting surface makes up a bunch of the detailed arguments. They look reasonable, except that the starting surface pull (see the arguments to the version of CreatePatch that exposes all controls) is set to 1, which makes the plane that gets cooked up have an influence on where the surface goes. If I change that to 0 (in a test build) I get virtually the same surface within the same tolerance to the input curves as with the command except that the grid is shifted sideways a little because the plane is cooked up a little differently.
Thus, the solution is for the version of CreatePatch that exposes all controls with the exception of the surface argument. I’l add something to the wish list.