Paying the Index Return Myself, if Not Met

My illustration shows that as long as S&P performs 6.3% every year, my policy will last to my age 121 and I can have a good retirement income.

My Question: If S&P does not perform 6.3% in any year, Can I contribute that amount in addition to the premium so that everything works as per the illustration?

Or it does not count if I pay? only the index performance will count?

Thanks

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