Audi TT gas gauge

I have been reading about gas gauges being inaccurate or 1/2 tank off etch. The problem resides not in the instrument cluster but in the contacts in the gas tank. I have been fortunate enough to find a gold clad ex Audi employee that works on his own. He advised me to add a bottle of Tectonics every three or four tank full before refilling. I did this and after about a Month, my gauge remains fairly accurate. It seems that a residue builds on the contact points and prevents them from opening and closing correctly. The remedy is considerably cheaper than what Audi dealers which to do and when you think about it, it seems like a perfectly reasonable explanation for the problem. I hope it helps some one.
David