ScheduleRow

One row of the quarterly capitalization schedule produced by simulate().

simulate() maintains a per-unit net quote and rounds it to the series’ SeriesMetadata.unitQuoteDecimals after each completed quarter. The holding’s booked net value is then round(units × unitFaceValueEur × unitQuoteAfter, 2).

Gross interest, IRS withholding, and net interest are booked in real EUR at the holding level each quarter:

interestNet is the movement in the booked value, balanceAfter less the previous quarter’s. IGCP credits nothing directly — it moves the quote — so the value’s movement is what was credited, and net interest computed any other way would not sum to the value the same result reports.
interestGross is cent-rounded from units × unitFaceValueEur × previousUnitQuote × quarterlyRate.
irsWithheld is interestGross − interestNet: the gross less what reached the holder. It is deliberately not irsRate × interestGross. An IGCP declaration under CIRS Article 119º nº 3 reports 55,95 EUR withheld against 199,75 EUR of gross income for a 2025 tax year, where 28% of that gross is 55,93 — so the rate is not what IGCP applies to arrive at the withholding.

As a consequence, schedule rows reconcile exactly with the matching totalInterest* headline fields and with currentValueNet.

One caveat, reachable only through an irsRate override: the quote is rounded per unit at five decimals while the gross is rounded to cents over the whole holding, so the two carry a residue that scales with the unit count. A real 28% withholding absorbs it invisibly. A rate low enough for the residue to exceed the withholding would make irsWithheld negative, which cannot happen, so there the gross gives way instead and equals interestNet — with nothing withheld, the gross is what was credited.