For every payment method except for SEPA bank wire you will get the amount stated at the transaction if you paid on time.
For SEPA bank wire the amount of coins are calculated the day it is received on the LiteBit bank account with the current exchange rate.
You place an order Monday for 100 euro and would get 15 Cloak if the payment was received at this moment.
Tuesday the 100 euro is received. The 100 euro is now worth 18 Cloak. 18 Cloak is sent to the wallet of the customer.