Computed fields: Use with Flexifilter?

If Computed fields could be used with the Flexifilter module, then you could do some clever filtering too.

For example, I want to display some currency conversions on a page, which shows some prices: $20.20, $15.00, etc. I have another node which contains some basic currency exchange rates: $1 = 0.60362 GBP.

I want to filter my prices, and show $20.20 (=£12.19), $15.00 (=£9.05), where the new prices are computed from the filtered price, and the exchange rate in another node's field.