Flashbinder? Guitars, Inc. is negotiating with the bank for a lockbox system that is expected to reduce check collection time by 4 days. Flashbinder? Guitars' average check size is? $1,200 and any funds freed up by the new system will be invested in a money−market account that is currently paying? 2.5% annually. What is the most Flashbinder Guitars should be willing to pay the bank for the lockbox? service, assuming the bank charges a per−check processing? fee?