JSHOP: I wrote a file called amex_setPrices.php for the Lensbase site (in the admin folder) which sets price according to the following formula:
//Start: Price with VAT (e.g. EasySEPT, £18.00)
//Remove tax (VAT): £15.31
//Multiply by tax (VAT) rate: 15.31 * 119% = 18.22
//Multiply by exchange rate: 18.22 * 1.55 EUR = 28.24
//Round TO NEAREST DOLLAR (e.g. 28.2 = 28, 28.5 = 29): €28
I needed to apply this to both the $tableProducts, and a variation for $tableAdvancedPricing.
Checked into the LB source code.