Open AI API cannot sum integers

Im having trouble using the api to analyse a dataframe, i can do counts/distinct counts of categorical fields fine but when i try to do a simple sum i get wrong output, here is a example, when running this i get a different sum each time, has anyone looked at this , ive tried using different engines & datatypes but to no avail. thanks

import openai
import pandas as pd

openai.api_key = ‘xx’

df = pd.DataFrame({‘Net_Revenue’: [5, 2, 10, 25, 10, 7, 10, 20, 20, 40, 10, 1]})

def summarize_dataframe(df, prompt):

 response = openai.Completion.create(


summarize_dataframe(df, “Sum values in the column Revenue”)