div() or divide() with Xpath denominators

Is is possible to pass values retrieved using xpath() into the div([value]) or divide([value]) Math formatters?

I want to do something like this in an XML Map connector

[xpath(ConsignmentNode/DefinitionOfGoods/TotalKilos)  | div(xpath(ConsignmentNode/DefinitionOfGoods/TotalFull)| add(xpath(ConsignmentNode/DefinitionOfGoods/TotalHalf)) | add(xpath(ConsignmentNode/DefinitionOfGoods/TotalOversize))))]!--endfragment>!--startfragment>

which in pseudo code is

    Weight = Total Kilos / (Full + Half + Oversize)

Things like “….| div(2)” work, but I can’t seem to get it to work with values from other parts of the message.

Even simplifying to 

[xpath(ConsignmentNode/DefinitionOfGoods/TotalKilos) | divide(xpath(ConsignmentNode/DefinitionOfGoods/TotalHalf))]

gets the same error:

Formatter divide failed in the evaluation of <weight>[xpath(ConsignmentNode/DefinitionOfGoods/TotalKilos) | divide(xpath(ConsignmentNode/DefinitionOfGoods/TotalHalf))]</weight>. The error was: Error parsing BigDecimal value [xpath(ConsignmentNode/DefinitionOfGoods/TotalHalf)]. Value: 2000