I did try to convince the customer to use a time server and to use UTC but I failed at it Image may be NSFW.
Clik here to view.
And yes the DST dates can change from country to country... and even be change in a country... the example NI gives here is interesting : http://digital.ni.com/public.nsf/allkb/7E5CB910B1685C8B8625731A005FCB62
