The values of ITEM-TYPE are not consecutive values are 'L' OR 'R' OR 'Y' OR '6' OR '8' OR '9', also i found in manuals that ACCEPT/REJECT criterion is evaluated after the record has been selected/read. So i am not sure whether it is equvalent to IF condition (time taken to complete the process will be the same) ???
If no other ways then i would opt for 4 seprate read/find loops.
From the logic point of view - ACCEPT/REJECT are exactly like IF. From the performance point of view - ACCEPT/REJECT are slightly more efficient then IF, as Natural processes the record internally without waiting for IF. In any case, for huge file processing, it is not recommended to use ACCEPT/REJECT, and separate READs are a totally accepted solution.