Not sure why user has to press field exit.
Unless the field has CHECK(FE) keyword.
Without CHECK(FE) user can fill the field and it will advance to the next field
or leave the value left justified and tab to the next field
or leave the value left justified and press enter to submit the form
If the field is Both input/output a problem occurs leaving the field without pressing field exit if a previous value was in the field. Say the field conained __3 and the user typed 5 the field now looks like 5_3. When the screen is transmitted it will be processed as 503.