LOCK IN RATE ON CONTRACT AMOUNT

Hi, in the OT revision note, in the topic currency rate futures. you mentioned that the lock in rate only applies to the contract amount.The difference between actual and contract amount, either convert at spot on the date of transaction or better use forward rate if available on this amount.
my calculation based on the given example,
contract amount: 25*62,500*1.5896=$2,483,750
Actual amount =$2,500,000
under hedged amount =$16,250

1.is the above calculation correct as per the example given?
2.at what rate are we converting under hedged amount if forward rate is given ? my understanding sell rate
3.if under hedged amount is converted, am I to add to the contract amount converted to give total receipt?
thanks as always