Hys and thrshld is not same for all the cell. If it is same there is no use to send these information to UE. Also no standard defines the value , instead it defines the range of values. operator can select the range of values for both. Based on statistics of the deployment area operator will configure through OAM. How exactly they derive is implementation specific but some factors includes in calculations are coverage area, density, obstacles of the deployment area,availability of other cells etc.