For the PN, the redistribution function is simply dependent upon the mean RAW-Y value of the photons. This is time independent and averaging will work with any version of the EPN_REDIST CCFs. The MOS spatial dependence has been introduced explicitly into the EMOSn_REDIST CCFs from version 0052 onwards. Earlier CCFs do not support this feature and hence no averaging will be performed if these CCFs are used.