"Going to + Present Simple" vs "Going to + Present Continuous"

I am interested in distinguishing the difference between two patterns (to speak about a future plans, intentions, predictions, or intent to do something):

1. Going to + Present Simple
2. Going to + Present Continuous

I know both patterns and use them, however, I am not anymore sure what the exact distinction is between them. However, I am aware that Going to + Present Continuous cannot be used to Issue Commands unlike Going to + Present Simple:

• You are going to collect your right now! (Correct)
• You are going to be collecting your toys right now! (Incorrect)

Other examples where I cannot distinguish the difference:

• I am going to have a party next week.
• I am going to be having a party next week.

• We are going to carry out an experiment today.
• We are going to be carrying out an experiment today.
• Neither would I use to issue a command. I would just use the imperative "Collect you toy!". However, I think it's OK with negative, "You are not going to do that!" Commented Jun 21, 2017 at 11:47
• @dz420 there's nothing about "Going to + Present Continuous" Commented Jun 21, 2017 at 12:05

If the activity can be cast as one that recurs or is ongoing, the periphrasis for the future (BE + going) can be coupled with the continuous/progressive:

I'm going to be attending a conference in Chicago in July. We should try to get together. It would be great to catch up with you.

There, choosing the continuous over "going to attend" suggests that there may be several days on which an opportunity to get together may present itself.

• So "She's going to be having a baby" is absolutely wrong? Commented Jun 21, 2017 at 14:03
• having a baby is something "continuous". The baby doesn't just pop out like a cork from a champagne bottle. Why is that lady screaming, mommy? -- She's having a baby.
– TimR
Commented Jun 21, 2017 at 14:04
• Then "She's going to have a baby" means that one day she'll give birth? Commented Jun 21, 2017 at 14:07
• Yes, I'd say that to have there refers to the birth as something that will happen rather than as a process she will undergo. You must understand that these are nuances the speaker might not be fully conscious of when choosing between verb forms.
– TimR
Commented Jun 21, 2017 at 14:11