Hans,

you could try LNM tracing to find out, how often logical name
translations are being done.

$ ANAL/SYS
SDA> LNM ! provides some help...
SDA> LNM LOAD
SDA> LNM START TRACE
SDA> LNM SHOW TRACE/IDENT=epid
....
SDA> LNM STOP TRACE
SDA> LNM UNLOAD
SDA> EXIT

Volker.