Vy clusters

[Kurs74]

Hi guys,
After some advice. I was looking to upgrade by vy2 ss (04) with a 3 window cluster. So I did a bit of research and found out that I need the same series to avoid fuel gauge problems. I bought a berlina cluster off eBay, seller assured me that it was from 2004 series 2. I installed the cluster today and sure enough the fuel gauge is wrong. Mine says 10l left, new one says 45l. I double checked with the seller and he confirmed it was from series 2. My car is definitely series 2, as it's 2004 according to vin number. It's looking like a costly exercise in changing senders etc, The seller is willing to give me a refund, but I'm not sure why it's not working, since both are series 2. Anyway, any help appreciated,
Cheers,
Kurs

[DevilDRake]

I'm not 100% sure, but i heard that the needles and programs run backwards in this situation. There's a way to fix it but I'm not sure.