I'm just wondering if you realize that to accomplish what you're asking
would require someone to override a correct mathematical calculation.



The inequality you're experiencing is simply a risk associated with
truncating precise numbers and if that level of precision isn't
aesthetically pleasing or confuses your audience, rounding  to one
decimal place will probably get you where you need to be.



10% + 10% + 30% + 20% + 10% +20% = 100%



FYI - the numbers will finally equal 100.0000% when rounded to five
decimal places.