I read in a guidebook that if I want to buy two one ways (Leiden--Haarlem, Haarlem--Hoofddorp), I will be charged €1 surcharge per ticket. If I go to a ticket window, I will be charged €0.50 surcharge per ticket. So the surcharges aren't combined at a ticket window to €1.50/per ticket?
Also, can I buy these one ways in advance from a ticket window or machine (whichever is less money) from Amsterdam Centraal even though I'm neither beginning nor ending a rail trip there the following day? I'm arriving at Amsterdam Centraal from Hagen, Germany and would rather buy the next day's tickets when I arrive in the Netherlands and get it taken care of instead of doing it the following day. Thanks.