Here are three links to the simulation output from the my file. It has 4 form driven drill and tap operations on a grid. The first two use a larger mill and the second two a smaller end mill. Each pair of D&T operations should produce a honeycomb grid of blind holes. The smaller holes should begin to the left of zero and the larger ones to the right. This is a simple design of a holder for collets. Without changing any of the information in the D&T forms, but simply opening some up and subsequently closing them - followed by running the simulation - I get at least three different results. None of these results is the expected result. These are shown below. Clearly something is amiss. If I only do 2 D&T operations, I can get the expected result and everything works in the simulation and the subsequent post. But if I do 4 D&T operations, neither the simulation nor the post are correct.