EK Tier Miles Differ to Calculator

[k974]

Hi,

I'm currently in process of working out best Airline for 14 trips in 12months from BNE to LHR/DUB. The emirates calculator has the tier mileage return at

Saver 12,400
Flex 18,600
per return trip

but when I actually go to book it , it is giving me the following numbers

Saver 7,700
Flex 15,400

Thanks