120% deduction for software

I have the same problem. I cannot set the Dexxter cost category higher than 100%.

I would also like to know how to book this

I also have software that qualifies for this and would like to know as well :-)</

I have the same question, and can I still adjust this retroactively for the previous year's subscription?

Is it possible to get an answer to this via Dexxter, please?

I was searching there too, and found an other blog post where Dexxter itself provides an answer; I'll rephrase it here:

Go to the Reports / Income & expenses menu.

At the top right, there is a 'manual input' button where you can add a separate entry (cost category, amount, description). There, you can enter an extra 20% for the cost price of Dexxter or for other costs that can be deducted at more than 100%.