API registration - is it literally 72 hours or will 3 days before do?

[TimeIsAnIllusion]

When an airline asks for API information 72 hours before your flight does it literally mean that - or will 3 days before suffice even if its a few hours less than 72 hours?
Feeling stressed, rang airline they said 24 hours would be ok but I'm not sure that's true if it states 72 online in a big flashing box! I did it tonight, due to travel Sunday morning...

As long as you have done it before check-in there shouldn't be a problem.

Thank you for your reply Lizs , I am probably fretting over nothing then, I did give the info yesterday but its under 72 hours then as the flight is a morning one!