Twig-variable for raw-value of paid_to_date (better raw values for ALL numeric-values)

Hello,

for creating a mathematical logical invoice-design I need the raw value of paid_to_date-variable. Background: For invoice-corrections I'll have to write negative values of item-quantities. This leads to wrong negative signs, when I have paid the credit back. With a raw value I can at least correct the values of the PDF into a mathematical logical value by multiply it by -1.

For users it would be definetely easier to use twig for templates and invoices if there were only raw numeric values. So the handling is always the same for each and every money value. And one can easily calculate with them as the pre-formated ones cannot be altered by calculations or used for if-clauses for values higher, equal or lower than zero.