All assessments will not change at the same rate:

The key is properties should be assessed at their market values.

Between two years, the market values of different properties can change by different amounts.
 

Last year's assessment may have been wrong:

We do not know if last year's assessment was correct.  For example:

• Last year's assessment could have been too low.
• When you calculate the difference between last year and this year, your assessment may have gone up more than other properties.  BUT, this year's assessment might be correct.