When you code Db2PreCompile and set the default to a valid Build Proc in the ZDDOPTS BUILD member, ZDD does not honour this value and uses the default of blank. This also happens when performing a CHECKIN and Build from a component copied from your C drive and doing this ZDD uses the default values and does not use the values from the ZDDOPTS member.
It is NOT restricted for the following functions: 1) CHECKIN from personal – which allows it to be incorrectly added to package (see also item 1 above) 2) expand baseline library list – which in turn allows checkout
When new components are Checked-In with a corresponding BUILD in ZDD the ZDDOPTS BUILD parms are not honoured and it seems that ZDD assumes what the language is by the code in the member.