// Only store extra_callback_info1 if bit 0x80000000 is set. 
// When OpenTTD random production occurs extra_callback_info1 is 0
switch (FEAT_INDUSTRIES, SELF, switch_prod_change, [
  ((extra_callback_info1 & 0x80000000) != 0) && STORE_PERM(extra_callback_info1 - 0x80000000, 0),
  extra_callback_info1
]) {
  return CB_RESULT_IND_PROD_NO_CHANGE;
}