Lower Fare On March Zuiderdam

[spcl4cs_gal]

I know this topic has probably been discussed to death but what happens when the fare you booked your cabin for has gone down by at least $300. My brother and I initially booked for $2451CAD each (deposit only) for a SS cabin and now the HAL site is showing the same cabin at $2118. If at the time of final payment the price is still lower than what was initially listed, do we get a refund or will HAL just credit our shipboard account with the difference? What about an upgrade? And what happens AFTER we make the final payment and the price goes down.