oxPrice -> _ blNetPriceMode is not always true

Anyone can explain my why _blNetPriceMode is sometimes false, sometimes true?
I"m trying to get the value from _blNetPriceMode in oxarticles extended class but always get a null value.

Thank you.

_blNetPriceMode is in Price object, not in article object. I think price object has brutto/netto price inside, but this is not always used, as the article object calls brutto2Netto and netto2Brutto methods to calculate the values on its own.

But did you know why _blNetPriceMode sometimes is true and sometimes false?

Are you only checking one particular type (brutto or netto) of prices? On some spots shop has to display netto and brutto prices regardless of configured mode, probably this is an internal indicator if the price is netto or brutto