Switching power supply: why is the primary current rating 1A off when calculating power?
this supply says: 230V (170-264V) 1.5A. However my calculations for 240V is 0.416A.

You are comparing two different things.  The supply spec gives you the absolute maximum current it will ever draw under any conditions of output load, input voltage, temperature, phase of the moon, and what you had for breakfast.

You are calculating actual current for a specific case based on output power.  You are also doing it at significantly higher input voltage than the minimum.  Since this is a switching supply, the highest input current will occur at the minimum input voltage.  That alone accounts for a 40% reduction in input current.

Of course these power supplies aren't 100% efficient.  Look at the datasheet to see how much loss there is at full output power and the worst case input voltage.  That could account for another 15% reduction or so.  Then there is usually a significant cover your butt margin in specifying input current.  The manufacturer doesn't want to get caught with the supply ever drawing more than they said it would.  Since most customer aren't going to care that the supply might draw 1.5 A instead of 1 A, the manufacturer gives the more conservative worst case value.