Export sale accounting

I am a Export service provider of Websolutions.

Which date rate to be applied for booking sales in INR?

For eg: On date of transaction, US $ rate is Rs.55, So I book the sale at Rs.55 per USD and I receive the sale consideration after 1 week and US $ rate is Rs.56 per USD, however the bank deducts some amount for converting into INR i.e Rs.1.10 per USD and we receive net (56-1.10) Rs.54.90 per USD. so the entry at the time of booking and receiving consideration will be:

Sale booking:

Debtors        a/c    Dr.  55.00

To   Export Sale                 55.00

Receipt of amount:

Bank a/c                             Dr.    54.90

Loss on Exchange Fluc        Dr.     0.10

To Debtors A/c.                                     55.00

Pls. guide if its correct.