BOM Quantity Override

Ok.  So i have a model that is used to represent Oil.  It has all its
parameters set so that it shows in the BOM but the model is empty so
that it doesn't appear in the assemly.

I need to put 1.5 quarts in the motor.  ie... the qty column in the
bill needs to say 1.5

Can I override a cell in repeat region to show as 1.5?

How would you suggest I do this?  I can't exacly put 1/2 a model in
the assembly, and creating a new part number with the description "1.5
quarts of Oil" isn't an option.

Thanks