The applicability of the alternative transport conditions is to be determined on a
case by case basis depending on the available stability data. If allowed by the data,
the alternative short-term transport can be applied to each single transport along
the distribution chain. The alternative short-term transport differs from the tolerances
(worst-case situations) defined under section 1.1 in that it is an upfront allowed
excursion from the transport conditions.

Подскажите, пожалуйста, как перевести"upfront allowed excursion" - что здесь обозначает "upfront"?