I don't think it's possible without some extra work. It can be done if you make every column a separate expression. The column expressions and labels can still be dynamic depending on which months you want to show, but you won't be able to use the partial sum, so Total will need to be an expression as well.
If you want to stray from the basic pivot setup, it can get really messy, but I've been able to come up with some nice customized pivots after a little work.
