Hi,
If you want to have more digits you will have to modify your database structure.
The column "currency_rate" of the table "hikashop_currency" is " decimal(16,5) " which means that there is 5 digits after the comma.
If you change the database structure for the column, you will be able to store more digits.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.