Posted 8 January 2020, 1:17 am ESTUsing Version 12.45.20193.0
I noticed this in my project and can duplicate in the GrapeCity Spread Designer.
I created a percent cell type and set the maximum value to 999.99 and the minimum value to -999.99.
the cell will allow me to put in 9999.99 and -9999.99.
I then set the max cell type to 9999.99 and the min to -9999.99
the cell will then allow me to put in 99999.99 and -99999.99.
so it appears to be off by one digit in the allowable values.