I have done the fix to round the number right. I will release the update tomorrow.
Regarding the format, I am thinking probably I should just make it an option in the piechart module to allow user to specify a symbol of her/his choice (will perhaps account for the language/locale). While % would be default, the user can make it blank so that no such symbol is displayed. If that works for you, we can make the required change and roll out with the update. Do let us know.
Of course, for your requirement, you can just use a Custom CSS –
.labb-piechart .labb-percentage sup {
display: none;
}