That's probably true, Peter, but it does not make much sense (but when did the French ever have to make sense? - but I like the Spanish). If you have a fortnight's holiday, you might stop work on a Tuesday night and go back to work on Wednesday morning, two weeks later, you have had 14 days' holiday, not 15. But most holiday brochures have one week or two week holidays where you fly back on the same day of the week that you flew in on, so you have 7 (or 14) nights abroad, but need to take 8 (or 15) days leave (including the weekend).