I have been working on/with ERPNext for some time now, but had never tried to change much in terms of the output formatting – mostly because I was too afraid to mess anything up. I only made minor changes with the format builder/GUI tool, which, I must say – is not intuitive, and which I personally found a bit frustrating.
Anyway – it turns out that setting up custom formatting using Jinja2 is not as terrifying as I thought.
Here’s my 2nd attempt/updated 1st attempt (no longer hard-coded tax-rate), with some commenting within the code to explain what I am doing, and also where/why. The biggest difference between my version and the default, is that I show the excl-VAT, VAT and incl-VAT values separately.