How many overdue child support installments can lead to the debtor's civil arrest?
Under STJ Súmula 309 and CPC Article 528, §7, the coercive track that carries the risk of civil arrest reaches the three most recent installments that fell due and went unpaid before the enforcement action was filed, plus every installment that falls due while the case is pending, with no cap on how many of those later ones count.
Are older child support installments, beyond the three most recent, left uncollected?
They are not left uncollected, they simply fall outside the track that allows civil arrest: those older installments follow the CPC Article 523 expropriation track instead, with asset seizure and other property measures, plus a 10% penalty and 10% legal fees when the debtor fails to pay within 15 days.
Why does the enforcement filing date change the calculation result?
Because that date is what separates the installments that predate the filing, subject to the three-most-recent cap under CPC Article 528, §7, from the installments that fall due while the case is pending, which enter the coercive track with no cap; without that date, the calculator treats every installment as if it predated the filing.
Does the 10% CPC Article 523 penalty also apply to the CPC Article 528 arrest track?
Not by default: the CPC Article 528, §7 track uses personal coercion as its enforcement mechanism and does not automatically add a penalty or legal fees; those 10% figures are characteristic of the CPC Article 523 expropriation track, used for debt that does not fit the coercive route.