Lockboxes are never good for the merchant, besides delaying the batches there are fees the lender pays, most times they absorb them other times they pass it on to the merchant. Also, dont forget a reserve amount lockboxes would require to maintain and good luck getting a refund from the lender on those.

In the end, its better to switch the merchant to a an open processor you control, I dont like IPS as they eat up a lot of your residuals although for newbie brokers they are perfect.