I guess I don't know dates

I'm perplexed by something that must be very simple, yet I must be ignorant.
I can't get date data type fields populated in a PF correctly.

I have a DDS physical file with date data type fields defined with various
date formats (*USA, *ISO, *MDY, *JUL, etc.). The fields that permit use of
the DATSEP parameter do have it specified.

This file is populated (by RPGLE program X) from another file with numeric
values in the form of YYYYMMDD. Program X has stand alone date data type
fields defined with each of the various formats and separators (example
below).

d DateMDY s d datfmt(*MDY )
mm/dd/yy
d DateMDYSlsh s d datfmt(*MDY/)
mm/dd/yy
d DateMDYDash s d datfmt(*MDY-)
mm-dd-yy
d DateMDYPerd s d datfmt(*MDY.)
mm.dd.yy
d DateMDYComm s d datfmt(*MDY,)
mm,dd,yy
d DateMDYAmph s d datfmt(*MDY&)
mm dd yy
d DateDMY s d datfmt(*DMY)
dd/mm/yy
d DateDMYSlsh s d datfmt(*DMY/)
dd/mm/yy
d DateDMYDash s d datfmt(*DMY-)
dd-mm-yy
d DateDMYPerd s d datfmt(*DMY.)
dd.mm.yy
d DateDMYComm s d datfmt(*DMY,)
dd,mm,yy
d DateDMYAmph s d datfmt(*DMY&)
dd mm yy
d DateYMD s d datfmt(*YMD)
yy/mm/dd
d DateYMDSlsh s d datfmt(*YMD/)
yy/mm/dd
d DateYMDDash s d datfmt(*YMD-)
yy-mm-dd
d DateYMDPerd s d datfmt(*YMD.)
yy.mm.dd
d DateYMDComm s d datfmt(*YMD,)
yy,mm,dd
d DateYMDAmph s d datfmt(*YMD&)
yy mm dd
d DateJUL s d datfmt(*JUL)
yy/ddd
d DateJULSlsh s d datfmt(*JUL/)
yy/ddd
d DateJULDash s d datfmt(*JUL-)
yy-ddd
d DateJULPerd s d datfmt(*JUL.)
yy.ddd
d DateJULComm s d datfmt(*JUL,)
yy,ddd
d DateJULAmph s d datfmt(*JUL&)
yy ddd
d DateISO s d datfmt(*ISO)
yyyy-mm-dd
d DateISODash s d datfmt(*ISO-)
yyyy-mm-dd
d DateUSA s d datfmt(*USA)
mm/dd/yyyy
d DateUSASlsh s d datfmt(*USA/)
mm/dd/yyyy
d DateEUR s d datfmt(*EUR)
dd.mm.yyyy
d DateEURPerd s d datfmt(*EUR.)
dd.mm.yyyy
d DateJIS s d datfmt(*JIS)
yyyy-mm-dd
d DateJISDash s d datfmt(*JIS-)
yyyy-mm-dd

So, my program X logic moves the numeric value (in YYYYMMDD format) into the
DateISO field (defined as *ISO) and then moves the DateISO into each of the
stand alone fields shown above. The resulting values are all correct as
defined. That is, they contain exactly what they should contain (the same
date value, but in the field's format and separator). This is verified
using debugger.

However, when these values are then moved into the fields as defined in the
DDS PF (definition example shown below), they all get *MDY. Doesn't matter
how they are defined in the DDS.
A DUSASLSH L DATFMT(*USA)
A COLHDG('Date' 'USA Slash')
A DISODASH L DATFMT(*ISO)
A COLHDG('Date' 'ISO Dash')
A DEURPERD L DATFMT(*EUR)
A COLHDG('Date' 'EUR Perd')
A DMDYSLSH L DATFMT(*MDY)
A DATSEP('/')
A COLHDG('Date' 'MDY Slsh')
A DMDYDASH L DATFMT(*MDY)
A DATSEP('-')
A COLHDG('Date' 'MDY Dash')
A DMDYPERD L DATFMT(*MDY)
A DATSEP('.')
A COLHDG('Date' 'MDY Perd')
A DMDYCOMM L DATFMT(*MDY)
A DATSEP(',')
A COLHDG('Date' 'MDY Comm')
A DMDYNONE L DATFMT(*MDY)
A DATSEP(' ')

What is up with that? What am I ignorant of? What am I missing? There is
no DATFMT specification in any H spec. The system's default format
(QDATFMT) is MDY but I can't believe that is controling here.
I always thought moving a date data type field to another date data type
field simply changes the format of the value.

Straighten me out here, please.

Tom Garvey