TTWROR/IRR confusion after new taxonomy: performance neutral transfers

Hello, I introduced a new Taxonomy to separate my existing portfolio with all transactions since 2008, from a Lump sum that will be added soon, so the new money doesn’t mix up with actual IRR etc. So this Taxonomy has 2 categories, let’s say: old money, new money.

The category ‘new money’ is still 0 (contains only 1 debit account). The other category contains all other securities and accounts. Weirdly enough, when I ask the IRR with dataseries ‘old money’, this gives another IRR than with ‘complete portfolio’. While ‘new money’ is still totally empty. What do I do wrong?

What I notice: also the ‘invested capital’ ‘old money’ is less than what i see in ‘Entire portfolio’, in the calculation there’s also slightly less ‘performance neutral transfers’ while the ‘final value’ is the same in ‘entire portfolio’ and ‘old money’ at the moment. There is also more Delta in ‘old money’ than in ‘entire portfolio’, but the Absolute change is the same … It’s related to this Delta but I don’t get it.

Taxonomies are always evaluated pre-tax.

ok. The difference is indeed the taxes. OK. How can I separate ‘old money’ performance from ‘new money’ performance without using taxonomies?

Or put in another way: how can I exclude 1 deposit account from all the calculations (IRR, TTWR, Delta, Absolute Change, INvested Capital, Total)?

Edit: I started to use a filter. That’s a quite good solution, not so elegant as taxonomies but fine!