Ron, Biff,
thank you both for your answers. I now have a workaround but I still
cannot understand the behavior. I wonder, is it a glitch or is it
supposed to be the expected behavior?

BTW, I searched in .misc with keywords: OFFSET evaluation Peo Sjoblom
but it returned an irrelevant thread only. Does one of you have the
link to the thread?

Regards,
Kostis Vezerides