(1) If, on the date when the insolvency proceedings were opened, one or more of the claims to be set off against each other were conditioned, were immature or did not cover similar types of performance, such set-off may not be effected before its conditions are met. Sections 41 and 45 do not apply. Set-off is ruled out if the claim against which a set-off is to be effected will be unconditioned and mature before it can be set off.
(2) Set-off is not ruled out by the claims being expressed in different currencies or mathematical units if these currencies or mathematical units are freely exchangeable at the place of payment of the claim against which a set-off is to be effected. They are converted according to the exchange value applicable to this place at the time of receipt of the declaration of set-off.