(a) Unless otherwise instructed, a collecting bank in a good faith effort to secure payment of a specific item drawn on a payor other than a bank , and with or without the approval of any person involved, may waive, modify, or extend time limits imposed or permitted by this [Act] for a period not exceeding two additional banking days without discharge of drawers or indorsers or liability to its transferor or a prior party.
(b) Delay by a collecting bank or payor bank beyond time limits prescribed or permitted by this [Act] or by instructions is excused if (i) the delay is caused by interruption of communication or computer facilities, suspension of payments by another bank , war, emergency conditions, failure of equipment, or other circumstances beyond the control of the bank , and (ii) the bank exercises such diligence as the circumstances require.