Property Tax assessment appeal in Sacramento

[Raman Bindlish]

Has anyone tried appealing for Tax Assessment in Sacramento (or generally in CA)? My duplex was bought last year and I paid almost 20% below assessed value. Based on the market study, I see that it was not a steal and most of the duplexes in the area have comparable sale / listing price recently.  Also, my appraisal came out to same price as listing price. How do I go about appealing for tax assessment? Is it worth all the trouble to get 20% discount on property tax? I am cash flow positive with decent returns but it would definitely help me if I could reduce property tax further.

Also, I do not think I completely understand how property tax changes in CA based on a change in ownership. Based on sale price, does county re-assesses the property? What is the criterion for them to re-assess the property to lower value? i see that it immediately get assessed at higher price as soon as the purchase price is higher.