Is your feature request related to a problem? Please describe.
The Tax System could have more flexibility in configuring taxation.

Describe the solution you'd like
The variable for a flat tax and a percentage tax is currently governed by the same number, with a - used to represent a flat tax and a + used to represent a percentage tax. It should be possible to have both a flat tax and a percentage tax active at the same time. A percentage tax alone may not sufficiently penalise storing low-value high-volume items, and a flat tax will not sufficiently penalise storing high-value low-volume items.

It should be possible for the percentage tax to have a non-integer percent, i.e a 0.25% tax etc. Currently, this isn't supported. This is especially useful in cases where a 1% tax, the lowest percentage tax possible, is too high.

public static int sellingTax = 3;