Wow, that is totally different than how my dealer handled things.
When he wrote up my invoice he used whatever the worst exchange rate was from the previous 12 months. ($1.56 = 1 Pound Sterling)
When I put my deposit down in January of 2016 it was converted at that days exchange rate ($27000@1.41 + 18900 Pounds Sterling.
The day after Brexit I made another payment ($15000@1.38 = 10950 Pounds Sterling) And then the final payments with all the taxes title and delivery charges @1.35. Your way is more predictable as far as rate changes. I have to admit I watched the Brexit vote with white knuckles because it could have gotten very expensive for me.
