Life is invaluable but for insurance purpose, we need to put a value for life. So for that we take some % of the earning capacity of the proposer. For personal accident the maximum sum insured is restricted to 72 months salary/income of the proposer. So what is suggested above is that if you need more cover than buy life insurance (term insurance).
In the personal accident there are different parts. Read more about - What is an Personal Accident?. So there are following covers - Accidental Death (AD), Permanent Total Disablement (PTD), Permanent Partial Disablement (PPD) & Temporary Total Disablement (TTD) and some add ons e.g. 1. Education, 2. Employment , 3. Ambulance, 4. Medical Expenses, 5. Cost of Supporting Items, and 6. Cost of Travel etc. So for add-ons - only the maximum claim or proportionate claim amount is paid, in case of claim.