Hello Xavier, after some test this seems fixed for real.

Thanks!!!

One little note: isn't there a missing else clause in your source fragment? I
mean, there's a code path (the missing else to the inner if) that seem to
bring to not giving a value to ext_chg.

Of course, if ext_chg is default at zero, it does not matter and so even the
other else could be removed.

Thanks again,
   Mario