"has been calling my office": Why does this film use the present perfect tense here?

Question

From the movie Nappily Ever After:

[Violet's mom is straightening her daughter's hair with a hot comb.]

Violet: It seems like we've been preparing for this moment forever.

Violet's Mom: I told you one day your prince would come. So, does Clint still think the party's a surprise?

Violet: He has been calling my office, asking April for help...so I have been able to plan everything.

(For context: Clint is Violet's boyfriend, and April is her assistant. Violet found a box in Clint's pocket, and thinks that he is going to propose to her at her birthday night.)

I don't understand the use of present perfect in the bold parts. Doesn't past simple work here?

Answer 1

She has been able to plan. The present perfect is used because the planning is relevant in the present, the event is still to come and it is important to her. When she thinks back on the event later past simple would be appropriate, because then the event is in the past.

Answer 2

"Has been calling" implies that the action is repeated, over a period continuing up to the present.

"Called" or "has called" would suggest that he called once: it wouldn't rule out more than one call, but in the absence of any other cues, I think most people would interpret that as a single call.