Perplexed by my property value relative to comps. What is going on?

[Justin Moon]

Let me preface this by saying that I realize zillow zestimates aren't exactly the most accurate valuations metrics, but my issues are still puzzling.

I am located in Houston, and 2014 appraisals recently were released. Due to our strong economy and the booming energy business, a lot of people's home values have risen 20% percent or more, and I believe the average for the city was 17% this year. For instance, my assessed value for property tax purposes went from $229,000 to $273,000. Currently, my residence is a 3/2.5 condo in an 18 unit complex. So now to the questions...

1) I am seeing an odd disconnect on Zillow. My unit is the nicest unit in the complex, yet my property value has not gone up a penny according to Zillow. In fact, it has actually gone down about $1,000. When comparing other units in my complex, a lot of their zestimate values have gone up anywhere from 2%-4% the past month. I don't understand why this is happening. Not only is my unit the largest one in the complex, but it has the nicest view of downtown, and it is the ONLY unit in the complex with actual bedrooms. Since the condo complex is a loft layout, all of the other units have bedrooms without doors or a 4th wall.

2) I am failing to understand why my property value is so low on zillow with a HUGE disconnect compared to the county's appraised value, and this question ties partly into the issue pointed out above in issue #1. I'm looking at my county's property tax records, and there are 1/1.5 layouts with 1500 square feet appraising at $209,000. My unit is 2,060 square feet with a 3/2.5 layout and I actually have walled bedrooms and it is appraising for $273,000.

When comparing this to Zillow's zestimate, the $209,000 piece of property has a zestimate of around $250,000 while mine has a zestimate of $263,000. To me, this is rather odd.

3) Lastly, I had a question about the actual appraisal metrics used by the county. According to county records, my unit is a 2/2.5 but I clearly have three bedrooms in my unit. Why does the county believe my unit is a 2/2.5, how would I go about changing it, and would it be worth changing?