(1) Provisions in standard business terms are ineffective if, contrary to the requirement of good faith, they unreasonably disadvantage the party contracting with the user. An unreasonable disadvantage also may arise from the provision not being clear and comprehensible.
(2) In case of doubt, an unreasonable disadvantage is to be assumed to exist if a provision
1. is not compatible with essential principles of the statutory provision from which it deviates, or
2. limits essential rights or duties inherent in the nature of the contract to such an extent that attainment of the purpose of the contract is jeopardised.
(3) Subsections (1) and (2) as well as sections 308 and 309 apply only to provisions in standard business terms on the basis of which arrangements deviating from legal provisions, or arrangements supplementing those legal provisions, are agreed. Other provisions may be ineffective by virtue of subsection (1) sentence 2 in conjunction with subsection (1) sentence 1.