Transactions abroad or in a foreign currency

Ok thanks. I know mastercard is a good rate but it have to manually calculate how much i am loosing off the actual mid market rate.

For Euro
Mastercard: 1.276943
Mid Market: 1.26680

It turns out that Mastercard is about 0.8% over the actual mid market today. Weird.

Is this because Mastercard use the closing spot rate which was last recorded by Bank of England on Thursday as 1.2771?
http://www.bankofengland.co.uk/boeapps/iadb/Rates.asp?TD=9&TM=Jun&TY=2016&into=GBP&rateview=D&POINT.x=13&POINT.y=12
(Not sure why it doesnโ€™t post fridayโ€™sโ€ฆ Explain)