Low Order Fee by MFG for Open Cart

We have a low order fee extension installed on our website, but only lets us apply to the total order amount. We need to have this be applied to a specific mfg. For instance, for our typical customer there is no min. order fee across the board. We recently took on a new mfg that requires a min. order so if a customer is ordering product from this one particular mfg, they must purchase a min. of $250 or get a certain dollar amount applied to their order. Looking to have someone modify the current extension, or write a new one for our shopping cart. Using OpenCart 1.4.9.6