You have the option of arps coming in the second you ask for them, but the BIG difference is, they ALWAYS start on the 'one'.

Ask for an arp on the 'two' or the 'three', it will start alright... but it will start on the 'one' no matter when you ask for it. So the only way you don't mess up the timing is to always set it for waiting until the 'one' of the next bar.

UD, you talking about arrangers or WS's? AFAIK, Korg WS's have the same issues.