This week I needed to make back-to-back purchases of Meet&Assist airport services, so I used this as an opportunity to check for differences in conversion rates between my Amex Platinum and Chase Sapphire Reserve.
In both cases the charge was 179 Euros made on 7/20.
Amex Pre-auth transaction alert: $200.75
Amex Posted amount: $201.23
Chase Pre-auth transaction alert: $201.23
Chase Posted amount: $201.23
I was a bit surprised that there was no difference between the final posted amounts.