AD7799 Conversion

I have AD7799 in my circuit with analog 5V supply and a separate 5V reference voltage. 

Internal Gain =1. Based on the datasheet analog inputs can not exceed 5V+30mV. But my analog inputs can read up to 5.5V (and power supply is still 5V). 

Does this have any impact on the conversions? May be the conversions be wrong. I expect when 5.5V is at the input, the output should be 0XFFF.