Occasionally when you work these increases on a project, the item will ruffle or cup anyway. I think it maybe has something to do with the yarn type. When this happens, unravel the piece back to the beginning of the round. Work a straight round without any increases, then resume the decreases on the next round. You may have to do one or two straight rounds in between increase rounds to make this lie flat. This is perfectly acceptable.
Welsh corgis are cool.