Hi everyone, before my first question, I'd like to say that this forum is really great and I've been an intrigued lurker for a while.

I have originated a couple of Oneworld Explorers in Business class over the past year from countries outside the UK (mainly thanks to you folks). My latest one is a ticket out of Sweden (DONE4) bought from BA.
I recently made changes to all four of my intra-Asian segments;
originally HKG-BKK-HKG-SIN-HKG became
HKG-CMB-HKG-CMB-HKG.

I was charged at US$75 PER CHANGE- i.e. I paid $300 in total for the rerouting. I thought that the charge should be $75 in total no matter how many changes one makes (as long as no extra continents are added of course). I explained my understanding of the rules to BA before I paid, but someone went ahead and wrote in my booking that the total charge should be $300 and that is what I had to pay to get the ticket rerouted.

Browsing through this forum, I have come across several posts where more than one change seems to have been made for a total charge of $75.

Am I entitled to a refund of $225 from BA?
Any help would be much appreciated.
Jed