Multiple Freight Modifiers in OM - Min/Max Freight at line level

 I have seen many notes where OM documentation that says if you have more than one Freight and Special Handling Modifiers, only one will be applied.  I do not have the document id handy, but there was also one that suggested using buckets would allow you to in effect get around this limitation.  I have tried multiple setups trying to get it work, all unsucccessfully.  Any insight into this issue (other than the Enhancement Request that is out there?)?

Our requirements are to charge freight at line level, and also impose a minimum/maximum freight amount based on ship method.  The calculation is a percentage of total line amount based on a tiered rate structure chosed based on total order amount.  Our goal was to not have to resort to a Custom price formula.  We actually have the min/max freight at line level working per specifications; however, we now also need to be able to also include a discount for shipments in close proximity to our shipping location, and discounts on freight calculated on certain high cost, low weight items.