I hope this helps clarify something…
It will round up OR down depending what the value after the decimal is. Up if its >= .5 and down if it is < .5
It will round up as long as there is any value after the decimal. So 1.7 rounds up to 2 and 9.00000001 would round up to 10. This might help people when it comes to figuring out how many days till the launch.
As a side note, depending on what order you have your variables in when you calculate the time difference, you may get a negative number.
This will give you the absolute value of a number. So whether you have a negative number or not, this will give you a positive number to work with. When comparing dates, who knows if the date is in the future or the past. I believe this should allow you to calculate for both.