you do need to send in a 4138 stating that your chronic diarrhea is much worst than the examiner reported.
They may come back and lower it due to the way it should be rated as per the CFR. All of the get one rating.
4.113 Coexisting abdominal conditions.
There are diseases of the digestive system, particularly within the abdomen, which, while differing in the site of pathology, produce a common disability picture characterized in the main by varying degrees of abdominal distress or pain, anemia and disturbances in nutrition. Consequently, certain coexisting diseases in this area, as indicated in the instruction under the title "Diseases of the Digestive System," do not lend themselves to distinct and separate disability evaluations without violating the fundamental principle relating to pyramiding as outlined in 4.14.
4.114 Schedule of ratings -- digestive system.
Ratings under diagnostic codes 7301 to 7329, inclusive, 7331, 7342, and 7345 to 7348 inclusive will not be combined with each other. A single evaluation will be assigned under the diagnostic code which reflects the predominant disability picture, with elevation to the next higher evaluation where the severity of the overall disability warrants such elevation.