I've received an email form the exchange saying that the PACcoin will be facilitated to $PAC RCO and the total supply will be reduced from 100 billion to 3.5 billion in circulation. Besides, my balance of PACcoin will be swapped 1000:1 or 1000 current PACcoins for 1 new $PAC on the new blockchain.

Why the total supply is from 100 to 3.5, but my balance is from 1000 to 1? Shouldn't the ratio be the same?

I'm new to coin swap. Anyone know the reason why?