I have discussed this inconsistency with our team internally. The correct tx power values are provided under RF Specifications (table 20,21,22,23) in the datasheet. Please use those numbers for your development work. The max tx power (as 4dBm) mentioned in the 1st page is a mistake. We will correct it in the next revision of datasheet.
I appreciate your help in pointing out this datasheet inconsistency to us.