The SIZE parameter specifies the actual (SIZE=n) or estimated (SIZE=En) decimal number of records read from the input file. Unlike the FILSZ parameter, this number should not reflect any changes produced by INCLUDE/OMIT or exit processing, but should reflect SKIPREC and STOPAFT processing.
If the FILSZ parameter is not specified and SIZE=n is specified, MFX will terminate unless exactly n records are processed. If the FILSZ parameter is specified, the SIZE value is considered an estimate whether or not it is preceded by an E.