Ok I tried everything and took measurements the front two holes are 1/2mm off. There is no getting around it, if you try to enlarge the big square hole then the two rear screws won't line up. Another plate is what's needed with the holes in the proper place!!
That is definitely not the stock rear diff case - I propose that the issue is likely in the other part, as I am certain my cnc machine didn't simply decide to place the holes incorrectly this one time after making the same part for years. Maybe there is something else in the way? I see the mis-alignment in the picture, but I am certain the plate is the same as every other lower plate I've made since making this kit the 1st time several years ago.