JLee - Here's the big dilemma of appealing property taxes in our fair state: In any year with the exception of the year of a reval, your taxes must be more than 15% off in order to prevail on appeal. This gives the assessor a huge advantage, and you an huge hurdle. That's why I waited till the reval to do it.
The State of NJ mandates that the towns must do revals at least once every 10 yrs., but a lot of towns drag their feet on it b/c of the big expense. The State of NJ finally ordered our town to do it after many years, but then some other issues that cost the town a lot of $ came up, and they managed to get waivers from the state until it amounted to 19 yrs. before my town undertook it. On the other hand, the tiny town next to ours revals 1/3 of their properties every year on a rolling basis, so property owners there get (what I'd personally call) the only fair shot at it every 3 yrs.
Point being, it's important to know when your town will hold its next reval if you want to appeal in NJ, b/c you'll have a much greater chance of success that year. As for a factual error on your property record card like in your case, you can go point it out to the assessor at any time, and he's supposed to work with you to correct and adjust if you can prove it's incorrect. It might not make a huge difference in your taxes for .09 acres, but it should be worth a try.
As for what I disputed, I argued that the house was an eventual teardown on which we had been doing only the absolute minimal maintenance. And I took him through the house and he agreed that that was the house's eventual fate.
Lady Stash, are you by any chance in CA?