Raymond Giuseppi and other respondents.
This is the part of the debugger that allows you to see an internal table in an ALV. It's not one he's created himself.
I used this test program:
TYPES: BEGIN OF test_ty,
int TYPE i,
pd TYPE dmbtr,
END OF test_ty.
DATA test_record TYPE test_ty.
DATA test_table TYPE STANDARD TABLE OF test_ty WITH NON-UNIQUE KEY table_line.
DO 4 TIMES.
test_record-int = sy-index.
test_record-pd = test_record-int / 3.
INSERT test_record INTO TABLE test_table.
ENDDO.
And I see the decimals in the ALV view of the table. Abap stack 7.31. So I suspect this is something to do with your ABAP stack version/patch/kernel patch.