I had a similar issue, which was costing me about £700 a medical, (every 6 months!) I contacted the CAA medical division to ask about this and was told that the information given is only a guideline and not definitive. I was also told it was my prerogative to choose another AME, who possibly had a different view on this issue.
I did this and now have no issue with getting a class 1, just the usual advice about losing some weight.