Please show, in the form of a working sas data step, the data from your sample, and then, also in the form of a sas data step, what you expect the result to look like. Help us help you.
I presume LOCF is last-obs-carried forward. What are BOCF and WOCF? "best" and "worst" obs carried forward? If so, what is your definition of best and worst? Also, is the AVAL variable the only one to be processed for LOCF, BOCF, and WOCF? It's the only one with a missing value, so it's the only one for which LOCF would have an impact.