Unfortunately, this is a very sensitive command. 1st of all, You might extend the edges of the primary surface so you are not trying to deform the edge. This can be trimmed later.
As for channels, the variable section sweeps might serve you better. This requires trims and merge features as well as rounds to sew everything back together.
Before all is said and done, you will have a lot of features of different types to bring it all together. This certainly falls under the advanced Creo surfacing classification. Save often and if you suspect a serious corruption has occurred, backtrack to an earlier version.
How much contour are you shooting for?