Record Lock under Commitment Control

Hi,

I have a job running under Commitment Control with Lock Level of *CHG and
Scope of *JOB.

Program A (RPGLE), which is in the call stack, opens a file with Commit,
reads and updates a record in the file. Another Program B (RPGLE), which
comes later in the call stack, also opens that file with Commit, but when
it tries to read the same record, finds it locked.

I found this under IBMs Commit Lock Level documentation:
Within the same job, a program can change a record that has already been
changed within the current transaction as long as the record is accessed
again using the same commitment definition. When using the job-level
commitment definition, the access to the changed record can be made from a
program running within any activation group that is using the job-level
commitment definition.

I am new to using commitment control. I understand that the record will be
kept locked until the transaction is committed, but I was thinking that
another program in the same job opening the file under Commit should be
able to access it. Can someone please provide some insight into this.
TIA