It matters. This has been asked before. Keep the generated voltage leg #3 away from control transformer primaries in the machine tool. Only use T1 & T2 for that, T3 being the generated leg. If you are lucky the terminology for your Haas L1,L2, & L3 will be happy with T1 to L1, T2 to L2, and T3 to L3. You have to check. All it takes is a simple ohm-meter check.