Thank you much for your reply ISTFlyer , that's a very helpful information, much appreciated!

If I understand you correctly, by booking this 'Flex Option' you got a full refund (100% of the whole ticket price, incl. all fees), i.e. all the money that you originally paid for the ticket (except the fee for the flex option). Given the fact that Pegasus offers this option for about EUR 10 on their international flights, I would say that this is a really good deal then! I can't think of any other airline offering full flex (especially the cancellation option) for a price of only EUR 10 more on their cheapest tickets!

I will certainly use this option in the future!

(about processing time of refunds: my experience is that also on foreign credit/debit cards the refunds - at least these that are made by the system automatically (I think so) - are processed in a very timely manner, i.e. within 2-3 working days)