Looking at my payment slips every month there is double digit % of withholding tax deducted from my gross salary. I am not sure if it is going to be the case in December (it will be my first payment slip since I have C permit). If I pay what Gemeinde asks me to pay wouldn't I pay twice my income tax (once deducted from the salary by employer, second time advance amount asked by Gemeinde)?
Once the change is done in their systems it is much faster, I think in 2022 I got the final bill/return in 5 months.
In my case I also wrote them a couple of sentences, saying something like "as you can see I paid X chf via Quellensteuer and X chf via the provisorische Rechnung, which makes a total of X".
BTW, when I switched from tax at source to tax bills my employer didn't change anything despite being notified. I had to remind them to fix this.
And for the change to C permit, even if you do end up paying Quellensteuer for December, you'll declare it all on your tax return which will be from January to December.... and you will then pay (or get a refund) for the difference between Quellensteuer (which is averaged for the whole canton) and your local town. Some towns the tax will be higher, some lower, but you may also be able to claim deductions for things in your tax return which you were not claiming before, so do not worry that the tax will be a lot higher - it probably won't.
Our 2021 tax returns were lodged in around September 2022 and we just received the final bill. In Zurich Canton it used to take longer, but they made some huge upgrades to the system and I think also cleared the backlog during the covid years (or maybe they just needed more money to flow in faster, and employed more staff, I don't know).... but either way, even as we delay lodgement officially to later in the year, we are getting ours settled right now - each one for the past 4-5 years has been processed faster. ... but now 2022 won't be due for lodgement (with agreed delay) until september 2023.... but we can expect it to be settled by the end of 2023. Most cantons the normal lodgement date is end march and then you could get your settlement in 4-6 months, possibly even sooner.
And for estimates, what you may find is a delay between switching systems where you do not have a bill so you can't make advanced payments. You have three options:
1. Put the amount needed for tax into a savings account until you get your bill.
2. Go to the Gemeinde and request they issue you an interim document so you can start to pay the tax in ahead of time.
3. Ignore the fact that you are now getting a lot of extra money into your account, spend it then freak out later when you get a huge tax bill.
Did you know the' tradition' of having a 13th salary which usually involves taking a slice from your monthly salary then paying it back to you as extra salary in November/December and July/August is really about giving you extra cash flow to pay your taxes (and to inject cash into the economy in the two big holiday periods).....
When you file your declaration they will take into account Quellensteuer paid for 11 months of 2022. Worst case they may apply interest for the amount you didn’t pay in the provisorische Rechnung but I would contest it. In any case it’s better than having the equivalent of circa 2x your yearly tax expense locked up with the state.