What could I do? I legitimately worked that amount of time (in average) as I was working weekdays and weekends. Should I refuse the ITA and wait until I have 1 year of Canadian work experience and apply under CEC?Normally, if you are not claiming points for some work experience you should include it in the personal activities section. However, this may be questioning the visa officer whether your farm experience is legit as it is too many working hours per week altogether. It's good that you were able to afford those hours, but most people wouldn't do it.
I just wish I could have prevented this by having listed both experiences in my work history in previous applications.