I think what that sentence means that there is no actual charge on values up to 50K, as in the past you would have been charged a set fee or a percentage on this. Now due to EU rules you cannot be charged for that. So no transaction charge.
But the cheque itself has a charge, but I don't know how they decided on 13 Euro. I just know I never use cheques because one time I realised there was extra charges attached. It's the very fact it's a cheque is my understanding that is causing this charge, the cheque has to be sent back to the originating country I think.
I tried to read the link you posted but it's too small and even printing it out I cannot read it.
Anyway, maybe you could telephone the foreign exchange transactions department in BofI as you're not getting the full story easily from AAM.