This should work for what you're looking to do. Neptune only works on minute intervals and use the whole minute programmed. So if you do this: "If Time 08:00 to 08:01 Then ON" it's on for 2 minutes. The 8:00 minute and the 8:01 minute. You then need to defer 1:30 so it's on only 30 seconds. Try it. At worst it will be on a full minute.
Whatever outlet you're using, set it to advanced and do the following.
Fallback OFF
Set OFF
If Time 08:00 to 08:01 Then ON
Defer 001:30 Then ON
If Time 012:00 to 012:01 Then ON
Defer 001:30 Then ON
If Time 016:00 to 016:01 Then ON
Defer 001:30 Then ON