I am not an expert on disability insurance, so I recommend everyone do their own research and speak to a disability insurance independent broker to get tailored advice, but if you have a "true own occupation" and "partial disability" coverage, then I think you would be covered, e.g. if you are a programmer that can no longer code more than half time due to carpal tunnel, I would think you could collect 50% disability even if you could work full time as a waiter.

Of course, it's likely harder to prove such a claim, as the insurance companies look out for fraud. But if you have a clear and well-documented history, medical files, etc., I would think you should be eligible.

Note that your megacorp group insurance policy is likely more limited, e.g. it may not have any coverage for partial disability.

Happy to be corrected by those more knowledgeable.