Just don't trust the search too much. Just Saturday afternoon I was reviewing a report containing some Slope/w results where the program had searched out nonsensical failure surfaces that gave lower factors of safety. This was due, I think, to some negative stresses created by the goofy geometry. (I've seen a similar thing before, but this time I only had the output sections, not the file, so couldn't verify.) I don't think I saw those so much from UTEXAS2 back in the olden days.