When the CO gives you a time limit for mailing documents?

[kiwis]

I got an email from the CO asking for further documents, and she said this:
"I have completed an initial assessment of the application and would like to request the below information be provided to our office by 26 July 2017."

Mailing things from the US to NZ can take some time. I mailed everything in what I thought was plenty of time and have a delivery estimate of July 26th ( ) but the tracking isn't updating, so I'm concerned it won't arrive on time. I've emailed the CO (did so as soon as I sent the package) with the tracking number and details of what was sent.

So my question is: How strict are they with these timelines? Should I contact the CO about the potential of the mail taking longer than expected?

Thanks!

[JandM]

Some time last year, the NZ government told INZ to start giving these very short deadlines, with the idea that this would speed up the work. However, COs know perfectly well that in the real world, people can't magic evidence out of thin air (when they have to ask a university, or another government, for instance) and FORCE the postal service to get things there by a certain date, so as long as the applicant has made contact within the time limit, telling them what they've done and that they will get the information there as soon as possible, there is not usually any problem, and they are reasonable about it.

[kiwis]

That's a relief, thanks once again JandM!