Penrith were entitled to spread their payout figure over as many years as they wanted. It didn't mean we suddenly had to pay more when their payments stopped. Two separate contracts. From the player's point of view, he only cares about getting his money across the length of the original deal.
So if he was on $450k at Penrith, over four years, that's $1.8M until 2023, plus whatever upgrade they frontloaded into his existing 2019 portion.
If he was then required to leave (in mid-2019) to free up space for Crichton, To'o and the rest, he might've found he could get $350k from Parra for the remaining four years (2020-2023). He would then only be out of pocket by $400k. Penrith could then have agreed to pay it, and they were free to spread it over as many years as they liked (e.g. 2020: $125k, 2021: $125k, 2022: $150k). Meanwhile our deal with the player was whatever was agreed between us. There's no reason we'd have to suddenly pay more because Penrith's payout had ended.