This is not counted as forbidden ribaa so long as it is not based on a prior agreement and so long as this agreement between the two parties is reached on a one-on-one basis, without the involvement of any third party, because in that case the rulings on the settlement of business accounts would apply.
Si un tiers est impliqué , la réduction devient illégale parce assimilable aux retenus sur les billets ( fonds) commerciaux?