iAx Thanks so much for raising this — you're definitely not the only one who’s run into this overpayment + reconciliation puzzle in Solo.
You're absolutely right that Solo doesn’t currently support credit notes in the traditional sense. While we know this is a bit of a sore spot, overpayment scenarios are on the roadmap as part of future invoice and refund improvements.
In the meantime, the steps you've taken make a lot of sense. Creating a separate invoice for the overpaid amount is actually very similar to what we've recommended to other Soloists as a workaround — especially if your customer is happy to carry the extra as a credit towards future work.
So, no need to delete that “credit” invoice unless it’s causing confusion on your end. When it comes time to apply that credit, you can use it like a running tab against future invoices (just be sure to pop in a quick note for your customer so they can follow the math).
And just so you know — we’ve flagged your feedback with the team. Every vote like this (such as asking the question here in the forum) helps us shape the future of Solo.
Let us know if you want a hand tidying things up from here!