The form must be filled out within 10 days before the flight. Fill out the Entry Form within 10 days before your flight. What is the meaning of within in these sentences? Is it before 10 days before the flight? or Is it after 10 days before the flight? I.e. 8 days or 5 days or even 1 day before the flight is ok (even the same day as the flight)?
I understand that you can say, "within 30 days of receiving your application", but I am seeing more and more "within 30 days after your application is received". Is the latter grammatical?
Can you say "within 90 days after"? - English Language & Usage Stack ...
In most organizations, vacation days are usable at the employee's discretion, up to a certain yearly limit. Days off is a more informal phrase that includes a variety of kinds of paid-not-to-work days, including sick leave, maternal/paternal leave, floating holidays, national holidays, etc. Vacation days are a subset of days off.
"Vacation days" or "days off" - English Language & Usage Stack Exchange
There's also the perennial question of whether the last day ends on the multiple of 24 hours from the time when the deadline was given, if it means midnight of that day, or closing time of that day, or what. And does "7 days" mean 7 calendar days, or 7 business days? Etc.
In Australian English, "in the upcoming days" sounds strange. "In the coming days" is acceptable but probably too formal, I agree with @BoldBen's comment that "In the next few days" is a better choice. "In the next couple of days" also works, and arguably implies a slightly shorter time frame (the next few days could be 1-4 days, whereas the next couple of days probably means 2-3 days)
In 100-200 days means that it will happen no sooner than 100 days from now and no later than 200 days. Within 100-200 days means it could happen any time between now and 200 days, but most likely fall between the 100th and 200th day. Within within (wɪˈðɪn) prep in; inside; enclosed or encased by before (a period of time) has elapsed: within ...