After a lot of head banging from reading conflicting info through the forums, I finally learned that there is a possibility to add taxes to expenses natively (without custom fields tricks), yay - as seen here: Expenses taxes - Feature request - Self-Hosted | v5 - Discourse (invoiceninja.com)
I must say that this was not an intuitive find in my experience, as “Item tax rates” made me think of invoices, not expenses. It does not help that the taxes options on expenses only appear after the “Item Tax Rates” option has been turned on. May I suggest leaving this section displayed at all times, but greyed out until the Item Tax Rates have been turned on, with a temporary description or tooltip explaining to turn it on?
So anyway, I now see tax fields on Expenses, great.
I noticed however that if I add for an expense taxes by rate, the second tax field gets duplicated:
It still gets calculated only once, though, so that’s just a UI glitch.
I also noticed that I can’t get IN to show individual taxes in separate columns for expenses, I only get the total:
It’s weird, because I can add columns for separate tax rates and tax names:
So, it would be nice to get also Tax Amount 1, Tax Amount 2 and Tax Amount 3 - and of course “Tax Amount Total” could still be there as an option for those who want that.
I understand that if custom tax amounts are paid with custom names, IN probably cannot merge those tax names with registered taxes, but it would make sense IMO to have the option to select a registered tax (say, in my case, TVQ @ 9,975%) and override the amount it calculates to account for some rounding errors appearing on actual invoices I pay. So, say on an invoice I pay the TVQ tax, but instead of 9,975% it’s being calculated by the vendor @ 9,98%, I could still select “TVQ” in the dropdown menu, enter the real amount paid instead of letting IN do the calculation with the official rate, and have IN still list that amount in the “TVQ” column, where other, auto calculated of custom entered values would appear for other expenses.
Finally, it’s not related to expenses taxes directly, but I also noticed that expenses titles are fetched from the Public Notes field; however this makes titles overflow their container in the preview pane: