The error message indicates the beginning and ending procedures of one of the overlapping PERFORM ranges indicated by COBCH1663.
When no section name is present at the beginning of the PROCEDURE DIVISION, <procedure-name1> is displayed as {procedure division entry}. When a PERFORM range extends off the end of a program, <procedure-name-1> is displayed as {end procedure division}. When a PERFORM range begins at an ENTRY statement, <procedure-name-1> is displayed as {entry ""}.
$set ilshowperformoverlap
...
perform a thru c.
perform c thru f.
perform f.
goback.
*> errors are displayed as follows:
a section.
display "Running section a.". *> COBCH1663E Overlapping perform range: 3 entries
*> COBCH1664E perform range: a thru c
b section.
display "Running section b.".
c section. *> COBCH1664E perform range: c thru f
display "Running section c.".
d section.
display "Running section d.".
e section.
display "Running section e.".
f section. *> COBCH1664E perform range: f thru f
display "Running section f.".